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Kushanduka kwezvipembenene zvinotapukira kunosanganisira kurwisana pakati pekusarudza kwechisikigo, uko kunoita kuti zvipembenene zvivandudzike, uye kufamba kwemajini, uko kunoita kuti zvipembenene zvirasikirwe nemajini uye zviunganidze shanduko dzinokuvadza. Pano, kuti tinzwisise kuti kurwisana uku kunoitika sei pachiyero chemorekuru imwe chete, tinotsanangura chimiro che cryo-EM che ribosome yeEncephatozoon cuniculi, chipenyu che eukaryotic chine rimwe remajini madiki kwazvo. Kudzikira kwakanyanya kwe rRNA muE. cuniculi ribosomes kunoperekedzwa nekuchinja kusati kwamboitika, senge kushanduka kwe rRNA linkers dzakabatana kare uye rRNA isina bulges. Pamusoro pezvo, E. cuniculi ribosome yakapona kurasikirwa kwezvidimbu zve rRNA nemapuroteni nekugadzira kugona kushandisa mamorekuru madiki semagadzirirwo ezvidimbu zve rRNA zvakaora nemapuroteni. Zvose, tinoratidza kuti maumbirwo emamorekuru akafungidzirwa kwenguva refu kuti akaderedzwa, anoora, uye anogona kuchinja zvakanyanya ane nzira dzakawanda dzinoita kuti arambe achishanda pasinei nekuoma kwakanyanya kwemamorekuru.
Nekuti mapoka mazhinji ezvipembenene zvemabhakitiriya ane maturusi akasiyana ekushandisa zvinhu zvinovadzivirira, tinowanzo fanirwa kugadzira nzira dzakasiyana dzekurapa mapoka akasiyana ezvipembenene1,2. Zvisinei, humbowo hutsva hunoratidza kuti zvimwe zvinhu zvekushanduka kwezvipembenene zvinoenderana uye zvinonyanya kufanotaurwa, zvichiratidza hwaro hunogona kushandiswa pakurapa kwakakura muzvipembenene zvemabhakitiriya3,4,5,6,7,8,9.
Basa rekare rakaratidza nzira yakajairika yekushanduka-shanduka muzvipembenene zvehutachiona inonzi genome reduction kana genome decay10,11,12,13. Ongororo yazvino inoratidza kuti kana zvipembenene zvikasiya mararamiro azvo ehupenyu hwemahara uye zvikava zvipembenene zvemukati memasero (kana endosymbionts), majini azvo anochinja zvishoma nezvishoma asi zvinoshamisa kwemamiriyoni emakore9,11. Munzira inozivikanwa segenome decay, zvipembenene zvehutachiona zvinounganidza shanduko dzinokanganisa dzinoshandura majini mazhinji aimbova akakosha kuita ma pseudogenes, zvichikonzera kurasikirwa kwemajini zvishoma nezvishoma uye kudonha kwemutational14,15. Kudonha uku kunogona kuparadza kusvika 95% yemajini ari muzvisikwa zvekare zvemukati memasero zvichienzaniswa nemarudzi ane hukama hwakasununguka. Saka, kushanduka kwemajini emukati memasero ihondo pakati pemasimba maviri anopikisana: Darwinian natural selection, zvichitungamira mukuvandudzwa kwemajini, uye kudonha kwegenome, zvichikanda zvipembenene mukukanganikwa. Kuti zvipembenene zvakakwanisa sei kubuda muhondo iyi uye kuchengetedza mashandiro echimiro chazvo chemamorekuru hazvisati zvajeka.
Kunyangwe mashandiro ekuora kwemajini asina kunyatsonzwisiswa, zvinoita sekunge kunoitika nekuda kwekupararira kwemajini nguva nenguva. Nekuti tupukanana tunogara mumapoka madiki, asina zvepabonde, uye asina majini akawanda, hatukwanise kubvisa shanduko dzinokuvadza dzimwe nguva dzinoitika panguva yekudzokororwa kweDNA. Izvi zvinotungamira mukuunganidzwa kusingagadzirisiki kwekuchinja kunokuvadza uye kudzikira kwegenome retupukanana. Nekuda kweizvozvo, tupukanana harungorasikirwi nemajini asingachadiwi kuti rurarame munzvimbo iri mukati memasero. Kusakwanisa kwetupukanana kubvisa shanduko dzinokuvadza nguva nenguva kunoita kuti shanduko idzi dziungane mugenome yese, kusanganisira majini adzo akakosha.
Zvakawanda zvatinonzwisisa pari zvino nezvekuderedzwa kwemajini zvinobva pakungoenzanisa majenomu, pasina kunyanya kutarisisa shanduko dziri mumamorekuru chaiwo anoita mabasa ekuchengetedza imba uye anoshanda senzira dzekushandisa mishonga. Zvidzidzo zvekuenzanisa zvakaratidza kuti mutoro wekuchinja kwemajini anokuvadza mukati memasero unoita seunokonzera kuti mapuroteni nemanucleic acids apetwe nekusanganiswa, zvichiita kuti ave anonyanya kuvimba nechaperone uye ave nehanya zvakanyanya nekupisa19,20,21,22,23. Pamusoro pezvo, tupukanana twakasiyana-siyana—kushanduka-shanduka kwakazvimirira dzimwe nguva kwakaparadzaniswa nemakore anosvika mabhiriyoni maviri nehafu—twakasangana nekurasikirwa kwakafanana kwenzvimbo dzekudzora kunaka mukugadzirwa kweprotein5,6 uye nzira dzekugadzirisa DNA24. Zvisinei, zvishoma zvinozivikanwa nezvemhedzisiro yehupenyu hwemukati memasero pane zvimwe zvinhu zvese zvemacromolecule emasero, kusanganisira kugadziriswa kwemamorekuru kune mutoro unowedzera wekuchinja kunokuvadza.
Mubasa iri, kuti tinzwisise zviri nani kushanduka kwemapuroteni uye nucleic acids ezvipembenene zviri mukati memasero, takaona chimiro chema ribosomes eparasite iri mukati memasero Encephalitozoon cuniculi. E. cuniculi chinhu chakafanana nefungus chiri muboka re microsporidia ine parasitic ine ma genomes madiki eukaryotic uye nekudaro anoshandiswa semhando yezvisikwa kudzidza kuora kwe genome25,26,27,28,29,30. Munguva pfupi yapfuura, chimiro che cryo-EM ribosome chakaongororwa kune ma genomes akaderedzwa zvine mwero e Microsporidia, Paranosema locustae, uye Vairimorpha necatrix31,32 (~3.2 Mb genome). Zvimiro izvi zvinoratidza kuti kurasikirwa kwekuwedzera kwe rRNA kunobhadharwa nekuvandudzwa kwekubatana kutsva pakati pemapuroteni e ribosomal ari pedyo kana kuwanikwa kwemapuroteni matsva e msL131,32 ribosomal. Mhando dzeEncephalitozoon (genome ~2.5 miriyoni bp), pamwe chete neOrdospora yepedyo, dzinoratidza mwero wekupedzisira wekuderera kwemajini eukaryotes - dzine majini asingasviki 2000 eprotein-coding, uye zvinotarisirwa kuti ribosomes dzavo hadzisi chete dzisina zvidimbu zvekuwedzera zverRNA (zvidimbu zverRNA zvinosiyanisa eukaryotic ribosomes kubva kubacterial ribosomes) dzinewo mapuroteni mana eribosomal nekuda kwekushaya kwavo ma homologues muE. cuniculi genome26,27,28. Saka, takagumisa kuti E. cuniculi ribosome inogona kuratidza nzira dzaisazivikanwa dzekugadzirisa mamorekuru kuti asvike pakuora kwemajini.
Maumbirwo edu e cryo-EM anomiririra ribosome diki diki re eukaryotic cytoplasmic ribosome rinofanira kutsanangurwa uye anopa ruzivo rwekuti mwero wekupedzisira wekudzikiswa kwemajini unokanganisa sei maumbirwo, kuungana, uye kushanduka kwema molecular machinery ari mu cell. Takaona kuti E. cuniculi ribosome inotyora mitemo yakawanda yakachengetedzwa yekupeta kweRNA uye ribosome, uye takawana ribosome protein itsva, yaisazivikanwa kare. Zvisingatarisirwi, tinoratidza kuti microsporidia ribosomes yakagadzira kugona kusunga mamorekuru madiki, uye tinofungidzira kuti kutyorwa kwerRNA nemapuroteni kunokonzera kushanduka kwezvinhu kunogona kupa ribosome hunhu hunobatsira.
Kuti tivandudze kunzwisisa kwedu kwekushanduka kwemapuroteni nema nucleic acids muzvisikwa zviri mukati memasero, takasarudza kuparadzanisa spores dzeE. cuniculi kubva mutsika dzemasero emhuka ane hutachiona kuitira kuchenesa ribosome dzawo uye kuona chimiro cheribosome idzi. Zvakaoma kuwana huwandu hwakawanda hwe microsporidia inokanganisa hutachiona nekuti microsporidia haigone kurimwa mune zvinovaka muviri. Pane kudaro, inokura uye inobereka chete mukati mesero rinobata. Saka, kuti tiwane E. cuniculi biomass yekucheneswa kweribosome, takatapurira masero eitsvo emhuka dzemhuka dzemhuka RK13 nespores dzeE. cuniculi uye takarima masero aya ane hutachiona kwemavhiki akati wandei kuti E. cuniculi ikure uye iwande. Tichishandisa monolayer yemasero ane hutachiona yeinenge hafu yemita, takakwanisa kuchenesa spores dzeMicrosporidia dzinenge 300 mg uye takadzishandisa kuparadzanisa ribosomes. Takazovhiringidza spores dzakacheneswa negirazi beads uye takaparadzanisa crude ribosomes tichishandisa stepwise polyethylene glycol fractionation ye lysates. Izvi zvakatibvumira kuwana anenge 300 µg eE. cuniculi ribosomes mbishi kuti tiongorore chimiro chemuviri.
Takazounganidza mifananidzo ye cryo-EM tichishandisa masampuli e ribosome akabuda ndokugadzirisa mifananidzo iyi tichishandisa masks inoenderana ne ribosomal subunit hombe, small subunit head, uye small subunit. Munguva iyi, takaunganidza mifananidzo ye ribosomal particles inosvika 108,000 uye mifananidzo ye cryo-EM yakaverengerwa ine resolution ye 2.7 Å (Mifananidzo Yekuwedzera 1-3). Takabva tashandisa mifananidzo ye cryoEM kutevedzera rRNA, ribosomal protein, uye hibernation factor Mdf1 yakabatana ne E. cuniculi ribosomes (Mufananidzo 1a, b).
a Maumbirwo eE. cuniculi ribosome iri mucomplex ine hibernation factor Mdf1 (pdb id 7QEP). b Mepu ye hibernation factor Mdf1 yakabatana neE. cuniculi ribosome. c Mepu yechimiro chechipiri ichienzanisa rRNA yakawanikwa mumhando dzeMicrosporidian ne ribosomal structures dzinozivikanwa. Mapaneru anoratidza nzvimbo ye amplified rRNA fragments (ES) uye ribosome active sites, kusanganisira decoding site (DC), sarcinicin loop (SRL), uye peptidyl transferase centre (PTC). d Kuwanda kwema electron kunoenderana ne peptidyl transferase centre yeE. cuniculi ribosome kunoratidza kuti iyi catalytic site ine chimiro chimwe chete mu E. cuniculi parasite nevaya vanoibata, kusanganisira H. sapiens. e, f Kuwanda kwemaerekitironi anoenderana nenzvimbo yekutsanangura (e) uye chimiro chenzvimbo yekutsanangura (f) zvinoratidza kuti E. cuniculi ine masara eU1491 pachinzvimbo cheA1491 (E. coli numbering) mune mamwe maeukaryotes akawanda. Kuchinja uku kunoratidza kuti E. cuniculi inogona kunge iine hunhu hwemishonga inorwisa mabhakitiriya inorwisa nzvimbo iyi inoshanda.
Kusiyana nemaumbirwo akambogadzirwa eV. necatrix neP. locustae ribosomes (maumbirwo ese ari maviri anomiririra mhuri imwechete ye microsporidia Nosematidae uye akafanana zvikuru), 31,32 E. cuniculi ribosomes dzinosangana nemaitikiro akawanda e rRNA ne protein fragmentation. Kuwedzera denaturation (Zvifananidzo Zvekuwedzera 4-6). Mu rRNA, shanduko dzinonyanya kushamisa dzaisanganisira kurasikirwa zvachose kwe amplified 25S rRNA fragment ES12L uye partial degeneration ye h39, h41, uye H18 helices (Mufananidzo 1c, Supplementary Fig. 4). Pakati pe ribosomal proteins, shanduko dzinonyanya kushamisa dzaisanganisira kurasikirwa zvachose kwe eS30 protein uye shortened ye eL8, eL13, eL18, eL22, eL29, eL40, uS3, uS9, uS14, uS17, uye eS7 proteins (Zvifananidzo Zvekuwedzera 4, 5).
Saka, kudzikira kwakanyanya kwemajini eEncephalotozoon/Ordospora kunoratidzwa muchimiro chawo cheribosome: E. cuniculi ribosomes dzinosangana nekurasikirwa kukuru kwehuwandu hweprotein mu eukaryotic cytoplasmic ribosomes zvichienderana nechimiro chechimiro, uye hadzina kunyange zvidimbu zverRNA neprotein izvo zvakachengetedzwa zvakanyanya kwete muma eukaryotes chete, asiwo munzvimbo nhatu dzehupenyu. Chimiro cheE. cuniculi ribosome chinopa modhi yekutanga yemamorekuru ekuchinja uku uye chinoratidza zviitiko zvekushanduka-shanduka izvo zvakafuratirwa nekuenzanisa genomics uye zvidzidzo zvemukati memasero biomolecular structure (Supplementary Fig. 7). Pazasi, tinotsanangura chimwe nechimwe chezviitiko izvi pamwe chete nemavambo azvo ekushanduka-shanduka uye kukanganisa kwazvinoita pabasa re ribosome.
Takabva taona kuti, pamusoro pekucheka kukuru kwerRNA, E. cuniculi ribosomes dzine rRNA variations pane imwe yenzvimbo dzadzo dzinoshanda. Kunyangwe peptidyl transferase centre yeE. cuniculi ribosome ine chimiro chakafanana nedzimwe eukaryotic ribosomes (Mufananidzo 1d), decoding centre inosiyana nekuda kwekuchinja kwe sequence pa nucleotide 1491 (E. coli numbering, Mufananidzo 1e, f). Kucherechedza uku kwakakosha nekuti decoding place ye eukaryotic ribosomes inowanzo kuve ne residues G1408 naA1491 zvichienzaniswa ne residues dze bacterial-type A1408 naG1491. Kusiyana uku ndiko kunobva pakunzwa kwakasiyana kwe bacterial ne eukaryotic ribosomes ku aminoglycoside family ye ribosomal antibiotics nedzimwe diki molecules dzinonanga decoding place. Panzvimbo yekunyora manyorerwo eE. cuniculi ribosome, residue A1491 yakatsiviwa neU1491, zvichigona kugadzira imwe nzira yekubatanidza mamorekuru madiki akananga kunzvimbo iyi inoshanda. Iyo A14901 variant yakafanana iripowo mune mamwe ma microsporidia akadai seP. locustae naV. necatrix, zvichiratidza kuti yakapararira pakati pemhando dze microsporidia (Mufananidzo 1f).
Nekuti sampuro dzedu dzeE. cuniculi ribosome dzakabviswa kubva kuspores dzisingashande mumuviri, takaedza mepu yecryo-EM yeE. cuniculi kuti tione kubatana kweribosome kwakatsanangurwa kare pasi pekumanikidzwa kana mamiriro ekushaya nzara. Zvinhu zvinogara kwenguva refu 31,32,36,37, 38. Takaenzanisa chimiro cheribosome inorara kwenguva refu nemepu yecryo-EM yeE. cuniculi ribosome. Pakuisa dhaka, S. cerevisiae ribosomes dzakashandiswa mucomplex ine hibernation factor Stm138, locust ribosomes mucomplex ine Lso232 factor, uye V. necatrix ribosomes mucomplex ine Mdf1 neMdf231 factors. Panguva imwe chete, takawana cryo-EM density inoenderana ne rest factor Mdf1. Kufanana neMdf1 inosunga neV. necatrix ribosome, Mdf1 inosungawo neE. cuniculi ribosome, uko inovhara nzvimbo yeE yeribosome, zvichida zvichibatsira kuita kuti ribosomes iwanikwe kana tupukanana tusina simba mumuviri tuchirega kushanda (Mufananidzo 2).
Mdf1 inovhara nzvimbo yeE yeribosome, iyo inoita seyaibatsira kudzivirira ribosome kana zvipembenene zveparasite zvikasashanda mumuviri. Muchimiro cheE. cuniculi ribosome, takaona kuti Mdf1 inogadzira kusangana kwaisazivikanwa neL1 ribosome stem, chikamu cheribosome chinoita kuti tRNA yakabviswa mu ribosome iburitswe kubva mu ribosome panguva yekugadzira mapuroteni. Kubatana uku kunoratidza kuti Mdf1 inoparadzaniswa neribosome ichishandisa nzira imwecheteyo ne deacetylated tRNA, zvichipa tsananguro yekuti ribosome inobvisa sei Mdf1 kuti iitezve kugadzirwa kwemapuroteni.
Zvisinei, chimiro chedu chakaratidza kusangana kusingazivikanwe pakati peMdf1 negumbo reL1 ribosome (chikamu cheribosome chinobatsira kuburitsa deacylated tRNA kubva muribosome panguva yekugadzira mapuroteni). Kunyanya, Mdf1 inoshandisa kubatana kwakafanana nechikamu chegokora che deacylated tRNA molecule (Mufananidzo 2). Iyi molekile module modelling yaisazivikanwa kare yakaratidza kuti Mdf1 inoparadzaniswa neribosome ichishandisa nzira imwechete ne deacetylated tRNA, izvo zvinotsanangura kuti ribosome inobvisa sei iyi hibernation factor kuti iitezve kugadzirwa kwemapuroteni.
Pakugadzira modhi yerRNA, takaona kuti E. cuniculi ribosome ine zvidimbu zverRNA zvakapetwa zvisina kujairika, zvatakadana kuti fused rRNA (Mufananidzo 3). Muma ribosome anotenderera munzvimbo nhatu dzehupenyu, rRNA inopetwa kuita maumbirwo umo ma rRNA mazhinji anotanga pairi uye anopetwa pamwe chete kana kuti anodyidzana nemapuroteni e ribosomal38,39,40. Zvisinei, muE. cuniculi ribosomes, ma rRNA anoita seanotyora musimboti uyu wekupetwa nekushandura mamwe ma helices awo kuita nzvimbo dzisina kuvhurika dzerRNA.
Maumbirwo eH18 25S rRNA helix muS. cerevisiae, V. necatrix, uye E. cuniculi. Kazhinji, muma ribosomes anotenderera munzvimbo nhatu dzehupenyu, iyi linker inomonereka kuita RNA helix ine masara 24 kusvika 34. MuMicrosporidia, zvakasiyana, iyi rRNA linker inoderedzwa zvishoma nezvishoma kuita maviri single-stranded uridine-rich linkers ane masara 12 chete. Mazhinji eaya masara akarererwa kune zvinonyungudutsa. Mufananidzo unoratidza kuti parasitic microsporidia inoita seinotyora misimboti yakajairika yekupeta rRNA, uko rRNA bases dzinowanzobatanidzwa kune mamwe mabhesi kana kuti dzinobatanidzwa mukudyidzana kwerRNA-protein. Mu microsporidia, mamwe ma rRNA fragments anotora fold isina kunaka, umo yekare rRNA helix inova single-stranded fragment yakatambanudzwa inenge yakatwasuka. Kuvapo kwenzvimbo idzi dzisina kujairika kunobvumira microsporidia rRNA kusunga fragments dziri kure dzerRNA uchishandisa nhamba shoma yeRNA bases.
Muenzaniso unoshamisa wekushanduka uku kwekushanduka-shanduka unogona kuonekwa muH18 25S rRNA helix (Mufananidzo 3). Mumarudzi kubva kuE. coli kuenda kuvanhu, mabhesi eiyi rRNA helix ane manucleotide 24-32, achigadzira helix isina kurongeka. Mumaumbirwo eribosomal akamboonekwa kubva kuV. necatrix naP. locustae,31,32 mabhesi eH18 helix haana kuvharwa, asi nucleotide base pairing inochengetwa. Zvisinei, muE. cuniculi chidimbu ichi cherRNA chinova malinkers mapfupi 228UUUGU232 na301UUUUUUUU307. Kusiyana nezvidimbu zverRNA zvakajairika, malinkers aya ane uridine-rich haaunganidzi kana kuita kusangana kwakanyanya nemaprotein eribosomal. Pane kudaro, anogamuchira magadzirirwo akavhurika uye akavhurika zvizere umo tambo dzerRNA dzinotambanudzwa dzakatwasuka. Kuumbwa uku kwakatambanudzwa kunotsanangura kuti E. cuniculi inoshandisa sei mabhesi eRNA gumi nemaviri chete kuzadza mukaha we33 Å uri pakati peH16 neH18 rRNA helices, nepo mamwe marudzi achida kanenge kaviri mabhesi erRNA kuti azadze mukaha uyu.
Saka, tinogona kuratidza kuti, kuburikidza nekupetwa zvisina kunaka, microsporidia dzeparasitic dzakagadzira nzira yekubata kunyange zvikamu zve rRNA zvinoramba zvakachengetedzwa zvakanyanya mumarudzi ese ari munzvimbo nhatu dzehupenyu. Zviri pachena kuti, nekuunganidza shanduko dzinoshandura rRNA helices kuita mapfupi poly-U linkers, E. cuniculi inogona kugadzira zvidimbu zve rRNA zvisingawanzoitiki zvine nucleotides shoma sezvinobvira kuti zvisungirire zvidimbu zve rRNA zve distal. Izvi zvinobatsira kutsanangura kuti microsporidia yakawana sei kudzikira kukuru muchimiro chayo che mamorekuru pasina kurasikirwa nehunhu hwayo uye kushanda kwayo.
Chimwe chinhu chisingawanzoitika cheE. cuniculi rRNA kuoneka kwerRNA isina kukora (Mufananidzo 4). Mabulges manucleotides asina base pairs anomonereka kubva muRNA helix pachinzvimbo chekuvanda mairi. Mazhinji ma rRNA protrusions anoshanda semamorecular adhesives, achibatsira kusunga mapuroteni ari pedyo eribosomal kana zvimwe zvidimbu zverRNA. Mamwe mabulges anoshanda semahinji, zvichibvumira rRNA helix kugonya nekupeta zvakanaka kuti ibudise mapuroteni 41.
a Kubuda kwe rRNA (S. cerevisiae numbering) hakupo muchimiro che E. cuniculi ribosome, asi kuripo mune mamwe ma eukaryotes mazhinji b E. coli, S. cerevisiae, H. sapiens, uye E. cuniculi internal ribosomes. zvipembenene hazvina akawanda ema rRNA bulges ekare, akachengetedzwa zvakanyanya. Kukora uku kunosimbisa chimiro che ribosome; saka, kusavapo kwavo mu microsporidia kunoratidza kudzikira kwekupeta kwe rRNA mu microsporidia parasites. Kuenzanisa ne P stems (L7/L12 stems mubacteria) kunoratidza kuti kurasikirwa kwema rRNA bumps dzimwe nguva kunoenderana nekuonekwa kwema bumps matsva padyo nema bumps akarasika. H42 helix mu 23S/28S rRNA ine bulge yekare (U1206 muSaccharomyces cerevisiae) inofungidzirwa kuti ine makore angangoita mabhiriyoni 3.5 nekuda kwekudzivirirwa kwayo munzvimbo nhatu dzehupenyu. Mu microsporidia, bulge iyi inobviswa. Zvisinei, bundu idzva rakaonekwa padivi pebundu rakarasika (A1306 muE. cuniculi).
Zvinoshamisa kuti, takaona kuti maE. cuniculi ribosomes haana mabulge akawanda erRNA anowanikwa mune mamwe marudzi, kusanganisira mabulge anopfuura makumi matatu akachengetedzwa mune mamwe maeukaryotes (Mufananidzo 4a). Kurasikirwa uku kunobvisa kubatana kwakawanda pakati pema ribosomal subunits ne adjointe rRNA helices, dzimwe nguva zvichigadzira maburi makuru mukati me ribosome, zvichiita kuti E. cuniculi ribosome ive neburi rishoma kana tichienzanisa nema ribosome echinyakare (Mufananidzo 4b). Zvinoshamisa kuti, takaona kuti mabulge mazhinji aya akarasikawo muzvimiro zve ribosome zveV. necatrix neP. locustae, izvo zvakaregeredzwa neongororo dzekare dze structural31,32.
Dzimwe nguva kurasikirwa kwe rRNA bulges kunoperekedzwa nekukura kwebulges itsva padyo nebulge yakarasika. Semuenzaniso, ribosomal P-stem ine bulge yeU1208 (muSaccharomyces cerevisiae) yakararama kubva kuE. coli kuenda kuvanhu uye nekudaro inofungidzirwa kuti ine makore mabhiriyoni 3.5. Munguva yekugadzira mapuroteni, bulge iyi inobatsira P stem kufamba pakati pemafungiro akavhurika neakavharika kuitira kuti ribosome ikwanise kuwana zvinhu zvinoshandura uye kuzviendesa kunzvimbo inoshanda. MuE. cuniculi ribosomes, bulge iyi haisipo; zvisinei, bulge itsva (G883) inowanikwa mumabhesi matatu chete inogona kubatsira mukudzoreredzwa kwekushanduka kwakanyanya kweP stem (Mufananidzo 4c).
Ruzivo rwedu pamusoro pe rRNA isina mabulges runoratidza kuti kuderedza rRNA hakungogumiri pakurasikirwa kwezvinhu zve rRNA pamusoro pe ribosome, asi kunogonawo kusanganisira ribosome nucleus, zvichigadzira chikanganiso chemorekuru chakasiyana neparasite chisina kutsanangurwa mumasero anorarama ari ega. Mhando dzemhuka dzinoonekwa.
Mushure mekutevedzera mapuroteni e ribosomal ne rRNA, takaona kuti zvikamu zve ribosomal zvemazuva ano hazvigone kutsanangura zvikamu zvitatu zvemufananidzo we cryo-EM. Zviviri zvezvidimbu izvi mamorekuru madiki muhukuru (Mufananidzo 5, Mufananidzo Wekuwedzera 8). Chikamu chekutanga chakaiswa pakati pemapuroteni e ribosomal uL15 ne eL18 munzvimbo inowanzo shandiswa ne C-terminus ye eL18, iyo inopfupikiswa mu E. cuniculi. Kunyangwe tisingakwanise kuziva hunhu hwemorekuru iyi, saizi nechimiro chechitsuwa ichi che density zvinotsanangurwa zvakanaka nekuvapo kwemamorekuru e spermidine. Kubatana kwayo ne ribosome kunosimbiswa ne microsporidia-specific mutations mumapuroteni e uL15 (Asp51 ne Arg56), ayo anoita seanowedzera hukama hwe ribosome kune iyi molecule diki, sezvo ichibvumira uL15 kuputira morekuru diki kuita ribosomal structure. Mufananidzo Wekuwedzera 2). 8, data rekuwedzera 1, 2).
Mufananidzo weCryo-EM unoratidza kuvapo kwemanucleotide ari kunze kweribose akasungirirwa kuE. cuniculi ribosome. MuE. cuniculi ribosome, nucleotide iyi inogara panzvimbo imwecheteyo ne25S rRNA A3186 nucleotide (Saccharomyces cerevisiae numbering) mune mamwe maeukaryotic ribosomes mazhinji. b Muchimiro cheribosomal cheE. cuniculi, nucleotide iyi iri pakati pemapuroteni eribosomal uL9 ne eL20, nokudaro ichidzikamisa kusangana pakati pemapuroteni maviri. cd eL20 sequence conservation analysis pakati pemhando dze microsporidia. Muti wephylogenetic weMicrosporidia species (c) uye multiple sequence alignment ye eL20 protein (d) zvinoratidza kuti nucleotide-binding residues F170 neK172 dzakachengetedzwa muMicrosporidia yakajairika, kunze kweS. lophii, kunze kweMicrosporidia yekutanga, iyo yakachengetedza ES39L rRNA extension. Mufananidzo uyu unoratidza kuti nucleotide-binding residues F170 neK172 dziripo chete mu eL20 ye microsporidia genome yakaderera zvikuru, asi kwete mune dzimwe eukaryotes. Zvose izvi zvinoratidza kuti Microsporidian ribosomes dzakagadzira nucleotide binding site inoita seyakasunga ma AMP molecules uye dzinoshandisa iwo kudzikamisa kudyidzana kwemaprotein-protein mu ribosomal structure. Kuchengetedzwa kwakanyanya kweiyi binding site mu Microsporidia uye kusavapo kwayo mune dzimwe eukaryotes zvinoratidza kuti iyi nzvimbo inogona kupa mukana wekusarudza kupona kweMicrosporidia. Saka, pocket inosunga nucleotide iri mu microsporidia ribosome hairatidzike sechinhu chinoora kana kuti chimiro chekupedzisira chekuora kwerRNA sezvakatsanangurwa kare, asi kuti ipfungwa itsva inobatsira yekushanduka-shanduka inobvumira microsporidia ribosome kusunga zvakananga mamorekuru madiki, ichishandisa iwo semabhuroko ekuvaka mamorekuru. Kuwanikwa uku kunoita kuti microsporidia ribosome ive yega ribosome inozivikanwa kushandisa nucleotide imwe chete sechivako chayo chekuvaka. f Nzira yekufungidzira yekushanduka-shanduka inobva mukusunga nucleotide.
Huremu hwechipiri hwakaderera hwemamorekuru huri pakati pemapuroteni eribosomal uL9 ne eL30 (Mufananidzo 5a). Iyi interface yakambotsanangurwa muchimiro cheSaccharomyces cerevisiae ribosome senzvimbo inosunga 25S nucleotide yerRNA A3186 (chikamu cheES39L rRNA extension)38. Zvakaratidzwa kuti muma ribosomes eP. locustae ES39L akaora, iyi interface inosunga nucleotide imwe chete isingazivikanwe 31, uye zvinofungidzirwa kuti iyi nucleotide imhando yekupedzisira yerRNA yakaderedzwa, umo kureba kwerRNA kuri ~130-230 bases. ES39L yakaderedzwa kusvika kune nucleotide imwe chete 32.43. Mifananidzo yedu ye cryo-EM inotsigira pfungwa yekuti huremu hunogona kutsanangurwa ne nucleotides. Zvisinei, resolution yepamusoro yechimiro chedu yakaratidza kuti iyi nucleotide imorekuru ye extraribosomal, pamwe AMP (Mufananidzo 5a, b).
Takazobvunza kana nzvimbo yekusunga nucleotide yaionekwa muE. cuniculi ribosome kana kuti yaimbovapo kare. Sezvo kusunga nucleotide kuchinyanya kutungamirirwa nePhe170 neLys172 residues mu eL30 ribosomal protein, takaongorora kuchengetedzwa kwezvisara izvi mu4396 representative eukaryotes. Sezvakaitika pa uL15 pamusoro apa, takaona kuti Phe170 neLys172 residues dzakachengetwa zvakanyanya chete muMicrosporidia yakajairika, asi hadzipo mune dzimwe eukaryotes, kusanganisira atypical Microsporidia Mitosporidium neAmphiamblys, umo ES39L rRNA fragment isingaderedzwe 44, 45, 46 (Mufananidzo 5c). -e).
Kana zvabatanidzwa, data iri rinotsigira pfungwa yekuti E. cuniculi pamwe nedzimwe canonical microsporidia dzakagadzira kugona kubata zvinobudirira huwandu hwakawanda hwema metabolites madiki muchimiro che ribosome kuti dzitsigire kudzikira kwemazinga e rRNA nemapuroteni. Mukuita izvi, vakagadzira kugona kwakasiyana kwekubatanidza nucleotides kunze kwe ribosome, zvichiratidza kuti maumbirwo emamorekuru anotsiva nekubata ma metabolites madiki akawanda uye kuashandisa semagadzirirwo eRNA nezvidimbu zveprotein zvakaora.
Chikamu chechitatu chisina kuenzaniswa chemepu yedu ye cryo-EM, chinowanikwa muchikamu chikuru che ribosomal. Chiyero chepamusoro (2.6 Å) chemepu yedu chinoratidza kuti huwandu uhwu ndehwemapuroteni ane musanganiswa wakasiyana wezvisaririra zvikuru zvemacheni makuru, izvo zvakatibvumira kuziva huwandu uhwu sepuroteni ye ribosomal yatakaziva seYakatumidzwa zita rekuti msL2 (Microsporidia- specific protein L2) (nzira, mufananidzo 6). Kutsvaga kwedu kwe homology kwakaratidza kuti msL2 inochengetwa muMicrosporidia clade yegenus Encephaliter neOrosporidium, asi haipo mune mamwe marudzi, kusanganisira mamwe Microsporidia. Muchimiro che ribosomal, msL2 inotora mukaha unoumbwa nekurasikirwa kwe ES31L rRNA yakawedzerwa. Munzvimbo iyi, msL2 inobatsira kudzikamisa rRNA folding uye inogona kutsiva kurasikirwa kwe ES31L (Mufananidzo 6).
Kuwanda kwemaerekitironi uye modhi yeMicrosporidia-specific ribosomal protein msL2 inowanikwa muE. cuniculi ribosomes. b Mazhinji eeukaryotic ribosomes, kusanganisira 80S ribosome yeSaccharomyces cerevisiae, ane ES19L rRNA amplification yakarasika mumarudzi mazhinji eMicrosporidian. Maumbirwo akambogadzirwa eV. necatrix microsporidia ribosome anoratidza kuti kurasikirwa kweES19L muzvipembenene izvi kunodzorwa nekushanduka kweprotein itsva yemsL1 ribosomal. Muchidzidzo ichi, takaona kuti E. cuniculi ribosome yakagadzirawo imwe ribosomal RNA mimic protein semuripo unooneka wekurasikirwa kweES19L. Zvisinei, msL2 (ikozvino yakanyorwa seproteni yeECU06_1135 inofungidzirwa) uye msL1 dzine mavambo akasiyana uye ekushanduka-shanduka. c Kuwanikwa uku kwekugadzirwa kwemapuroteni e ribosomal e msL1 ne msL2 asina hukama nekushanduka-shanduka kunoratidza kuti kana ma ribosome akaunganidza shanduko dzinokuvadza mu rRNA yavo, anogona kuwana huwandu husina kumboonekwa hwekusiyana kwezvikamu kunyangwe muboka diki remarudzi ane hukama hwapedyo. Kuwanikwa uku kunogona kubatsira kujekesa mavambo nekushanduka kwe mitochondrial ribosome, inozivikanwa nekudzikira kwayo zvakanyanya kwe rRNA uye kusiyana kusingawanzoitika mukuumbwa kwemapuroteni mumarudzi ese.
Takazoenzanisa puroteni ye msL2 nepuroteni ye msL1 yakambotsanangurwa, iyo chete inozivikanwa microsporidia-specific ribosomal protein inowanikwa mu V. necatrix ribosome. Taida kuyedza kana msL1 ne msL2 zvakabatana nekushanduka-shanduka. Ongororo yedu yakaratidza kuti msL1 ne msL2 zviri mugomba rimwe chete muchimiro che ribosomal, asi zvine maumbirwo akasiyana ekutanga neetatu, izvo zvinoratidza kuti zvakabva pakushanduka-shanduka (Mufananidzo 6). Saka, kuwana kwedu msL2 kunopa humbowo hwekuti mapoka emarudzi e compact eukaryotic anogona kushandura mapuroteni e ribosomal akasiyana kuti atsive kurasikirwa kwezvidimbu zve rRNA. Kuwanikwa uku kunozivikanwa nekuti ma ribosome mazhinji e cytoplasmic eukaryotic ane puroteni isingachinji, kusanganisira mhuri imwe chete yemapuroteni e ribosomal 81. Kuonekwa kwe msL1 ne msL2 muzvikamu zvakasiyana zve microsporidia mukupindura kurasikirwa kwezvikamu zve rRNA zvakarebeswa kunoratidza kuti kuora kwekugadzirwa kwemamorekuru eparasite kunoita kuti tupukanana tutsvage kuchinja kwemutsiro, izvo zvinogona kutungamira mukuwanikwa kwatwo mumapoka akasiyana etupukanana.
Pakupedzisira, apo modhi yedu yakapedzwa, takaenzanisa kuumbwa kweribosome yeE. cuniculi neyaifungidzirwa kubva mugenome sequence. Mapuroteni akati wandei eribosomal, anosanganisira eL14, eL38, eL41, uye eS30, aimbofungidzirwa kuti haasipo mugenome yeE. cuniculi nekuda kwekushaikwa kwemahomologues awo kubva mugenome yeE. cuniculi. Kurasika kwemapuroteni akawanda eribosomal kunofungidzirwawo mune mamwe maparasite akawanda ari mukati memasero uye endosymbionts. Semuenzaniso, kunyangwe mabhakitiriya mazhinji anogara aripo aine mhuri imwechete yemapuroteni eribosomal makumi mashanu nemana, gumi nerimwe chete emhuri idzi dzemapuroteni ane mahomologues anoonekwa mugenome yega yega yakaongororwa yemabhakitiriya anorambidzwa. Mukutsigira pfungwa iyi, kurasikirwa kwemapuroteni eribosomal kwakaonekwa mukuyedza muV. necatrix neP. locustae microsporidia, asina mapuroteni eeL38 neeL4131,32.
Zvisinei, maumbirwo edu anoratidza kuti eL38, eL41, uye eS30 chete ndizvo zviri kurasika muE. cuniculi ribosome. Puroteni ye eL14 yakachengetedzwa uye maumbirwo edu akaratidza kuti nei puroteni iyi isingawanikwe mukutsvaga kwe homology (Mufananidzo 7). MuE. cuniculi ribosomes, nzvimbo zhinji dze eL14 dzinosunga dzinorasika nekuda kwekuora kwe rRNA-amplified ES39L. Pasina ES39L, eL14 yakarasikirwa nechimiro chayo chechipiri, uye 18% chete ye eL14 sequence yaive yakafanana muE. cuniculi neS. cerevisiae. Kuchengetedzwa kwe sequence iyi kwakashata kunoshamisa nekuti kunyangwe Saccharomyces cerevisiae neHomo sapiens—zvipenyu zvakashanduka makore mabhiriyoni 1.5 zvakasiyana—zvine anopfuura 51% ezvisaririra zvakafanana mu eL14. Kurasikirwa uku kusingawanzoitiki kwekuchengetedzwa kwemasero kunotsanangura chikonzero nei E. cuniculi eL14 parizvino ichinzi puroteni yeM970_061160 kwete sepuroteni ye eL1427 ribosomal.
uye Microsporidia ribosome yakarasikirwa neES39L rRNA extension, iyo yakabvisa zvishoma nzvimbo yekubatanidza mapuroteni e-ribosomal eL14. Kana ES39L isipo, puroteni ye-microspore ye eL14 inorasikirwa nechimiro chechipiri, umo iyo yekare rRNA-binding α-helix inodonha kuita loop shoma. b Kurongeka kwezvikamu zvakawanda kunoratidza kuti puroteni ye eL14 yakachengetedzwa zvakanyanya mumarudzi eeukaryotic (57% sequence identity pakati peyeast ne homologues dzevanhu), asi isina kuchengetedzwa zvakanaka uye yakasiyana mu microsporidia (mune iyo isingapfuuri 24% ye residues yakafanana ne eL14 homologue). kubva ku S. cerevisiae kana H. sapiens). Kusachengetedzwa kwezvikamu zvishoma uye kusiyana kwechimiro chechipiri kunotsanangura kuti nei eL14 homologue isati yambowanikwa mu E. cuniculi uye nei puroteni iyi ichifungidzirwa kuti yakarasika mu E. cuniculi. Kusiyana neizvi, E. cuniculi eL14 yakambonyorwa sepuroteni yeM970_061160. Izvi zvinoratidza kuti kusiyana kwemajini e microsporidia kuri kufungidzirwa zvakanyanya: mamwe majini ari kufungidzirwa kuti ari kurasika mu microsporidia akachengetedzwa, kunyangwe ari mumhando dzakasiyana-siyana; pachinzvimbo, mamwe anofungidzirwa kuti anoronga majini e microsporidia emapuroteni akasiyana-siyana (semuenzaniso, puroteni inofungidzirwa kuti M970_061160) inoronga mapuroteni akasiyana-siyana anowanikwa mune mamwe eukaryotes.
Kuwanikwa uku kunoratidza kuti rRNA denaturation inogona kukonzera kurasikirwa kukuru kwekuchengetedzwa kwezvikamu mumapuroteni ari pedyo eribosomal, zvichiita kuti mapuroteni aya asaonekwe kuti atsvagwe nehomology. Saka, tinogona kufungidzira zvakanyanya mwero chaiwo wekuora kwemamorekuru muzvipenyu zvidiki zvemagenome, sezvo mamwe mapuroteni anofungidzirwa kuti arasika achiripo, kunyangwe ari muchimiro chakachinja zvakanyanya.
Zvipembenene zvinogona sei kuramba zvichishanda semamorekuru azvo mumamiriro ezvinhu ekuderedzwa kwakanyanya kwemajini? Chidzidzo chedu chinopindura mubvunzo uyu nekutsanangura chimiro chakaomarara chemamorekuru (ribosome) cheE. cuniculi, chipenyu chine rimwe remajini madiki eeukaryotic.
Zvave zvichizivikanwa kweanoda kusvika makumi maviri emakore kuti mapuroteni nemaRNA molecules muzvipembenene zve microbial zvinowanzosiyana nemamorekuru avo akafanana muzvisikwa zvipenyu zve free-living nekuti hazvina nzvimbo dzekudzora kunaka, zvinoderedzwa kusvika 50% yehukuru hwazvo muzvipembenene zvipenyu zve free-living, nezvimwewo. . . kuchinja kwakawanda kunokuvadza kupeta nekushanda. Semuenzaniso, ribosomes dzezvisikwa zvidiki zve genome, kusanganisira zvipembenene zvakawanda zvemukati memasero uye endosymbionts, zvinotarisirwa kushaya mapuroteni akawanda e ribosomal uye kusvika chikamu chimwe muzvitatu che rRNA nucleotides zvichienzaniswa nezvisikwa zvipenyu zve free-living 27, 29, 30, 49. Zvisinei, mashandiro anoita mamorekuru aya muzvipembenene achiri chakavanzika, akadzidzwa zvakanyanya kuburikidza ne comparative genomics.
Chidzidzo chedu chinoratidza kuti maumbirwo emacromolecules anogona kuratidza zvinhu zvakawanda zvekushanduka-shanduka izvo zvakaoma kuwana kubva muzvidzidzo zvechinyakare zvemagene ezvipembenene zvemukati memasero nezvimwe zvipenyu zvinorambidzwa kugara (Supplementary Fig. 7). Semuenzaniso, muenzaniso weprotein ye eL14 unoratidza kuti tinogona kuwedzeredza mwero chaiwo wekuora kwemidziyo yemamorekuru mumarudzi ezvipembenene. Zvipembenene zvinofungidzirwa kuti zvine mazana emagene e microsporidia-specific. Zvisinei, zvatakawana zvinoratidza kuti mamwe emagene aya anoita seakakosha chaizvoizvo akasiyana-siyana emagene akajairika mune mamwe eukaryotes. Uyezve, muenzaniso weprotein ye msL2 unoratidza kuti tinoregeredza sei mapuroteni matsva e ribosomal uye tinorerutsa zviri mumashini emakemikari ezvipembenene. Muenzaniso wemamorekuru madiki unoratidza kuti tinogona kuregeredza sei hunyanzvi hwakanakisa muzvivakwa zvemasero zvezvipembenene zvinogona kuvapa basa idzva rehupenyu.
Zvikatorwa pamwe chete, mhedzisiro iyi inovandudza kunzwisisa kwedu musiyano uripo pakati pemaumbirwo emamorekuru ezvisikwa zvinodzivirirwa nezvinorarama pamwe chete nazvo muzvisikwa zvipenyu zvinorarama zviri free-living. Tinoratidza kuti michina yemamorekuru, iyo yagara ichifungidzirwa kuti yakaderedzwa, inoora, uye inosangana nekuchinja kwakasiyana-siyana kunokuvadza, pane kudaro ine seti yezvikamu zvisingawanzoonekwi zvakarongeka.
Kune rumwe rutivi, zvidimbu zverRNA zvisina kukura uye zvidimbu zvakasanganiswa zvatakawana mu ribosomes yeE. cuniculi zvinoratidza kuti kudzikiswa kwemajini kunogona kuchinja kunyange zvikamu zvemamorekuru epakutanga anochengetwa munzvimbo nhatu dzehupenyu - mushure memakore angangoita mabhiriyoni 3.5. kushanduka kwakazvimirira kwemarudzi.
Zvidimbu zve rRNA zvisina bundu uye zvakasanganiswa muE. cuniculi ribosomes zvinonyanya kufadza zvichienderana nezvidzidzo zvekare zvema RNA molecules mu endosymbiotic bacteria. Semuenzaniso, mu aphid endosymbiont Buchnera aphidicola, ma rRNA ne tRNA molecules zvakaratidzwa kuti zvine maumbirwo anonzwa tembiricha nekuda kweA+T composition bias uye huwandu hwakawanda hwe non-canonical base pairs20,50. Shanduko idzi muRNA, pamwe neshanduko muma protein molecules, zvino zvinofungidzirwa kuti ndizvo zvinokonzera kutsamira zvakanyanya kwema endosymbionts pa partners uye kusakwanisa kwema endosymbionts kutamisa kupisa 21, 23. Kunyangwe parasitic microsporidia rRNA ine shanduko dzakasiyana dzemaumbirwo, hunhu hweshanduko idzi hunoratidza kuti kudzikira kwekupisa uye kuvimba zvakanyanya nema chaperone proteins zvinogona kunge zviri zvinhu zvakajairika zvema RNA molecules muzvisikwa zvine ma genomes akaderedzwa.
Kune rumwe rutivi, maumbirwo edu anoratidza kuti parasite microsporidia yakagadzira kugona kwakasiyana kwekudzivirira rRNA nezvidimbu zveprotein zvakachengetedzwa zvakanyanya, zvichivandudza kugona kushandisa metabolites diki dzakawanda uye dziri nyore kuwana semienzaniso yechimiro che rRNA yakaora nezvidimbu zveprotein. Kuora kwechimiro cheMolecular. . Pfungwa iyi inotsigirwa nekuti mamorekuru madiki anotsiva kurasikirwa nezvidimbu zveprotein mu rRNA ne ribosomes ye E. cuniculi anosunga kune microsporidia-specific residues mumaprotein e uL15 ne eL30. Izvi zvinoratidza kuti kusungwa kwemamorekuru madiki ne ribosomes kunogona kuve chibereko chekusarudzwa kwakanaka, umo Microsporidia-specific mutations mumaprotein e ribosomal yakasarudzwa nekuda kwekugona kwayo kuwedzera hukama hwe ribosomes kumamorekuru madiki, izvo zvinogona kutungamira kune ribosomal organisms inoshanda zvakanyanya. Kuwanikwa uku kunoratidza hunyanzvi hwakangwara muchimiro che molecular che microbial parasites uye kunotipa kunzwisisa kuri nani kwekuti parasite molecular structures dzinochengetedza sei basa radzo pasinei nekushanduka-shanduka kunodzikira.
Parizvino, kuzivikanwa kwemamorekuru madiki aya hakusati kwanyatsojeka. Hazvisi pachena kuti sei kuoneka kwemamorekuru madiki aya muchimiro che ribosomal kwakasiyana pakati pemhando dze microsporidia. Kunyanya, hazvisati zvajeka kuti sei kubatana kwe nucleotide kuchionekwa mu ribosomes dze E. cuniculi ne P. locustae, kwete mu ribosomes dze V. necatrix, pasinei nekuvapo kwe F170 residue mumapuroteni e eL20 ne K172 e V. necatrix. Kubviswa uku kunogona kukonzerwa ne residue 43 uL6 (iri padyo ne nucleotide binding pocket), inova tyrosine mu V. necatrix kwete threonine mu E. cuniculi ne P. locustae. Bulky aromatic side chain ye Tyr43 inogona kukanganisa kubatana kwe nucleotide nekuda kwe steric overlap. Neimwe nzira, kudzima kwe nucleotide kuri pachena kunogona kunge kuri nekuda kwe resolution yakaderera ye cryo-EM imaging, iyo inotadzisa kuumbwa kwe V. necatrix ribosomal fragments.
Kune rumwe rutivi, basa redu rinoratidza kuti maitiro ekuora kwemajini anogona kunge ari simba rekugadzira. Kunyanya, chimiro cheE. cuniculi ribosome chinoratidza kuti kurasikirwa kwe rRNA nezvidimbu zveprotein mu microsporidia ribosome kunogadzira kumanikidzwa kwekushanduka-shanduka kunokurudzira shanduko muchimiro che ribosome. Mhando idzi dzinoitika kure nenzvimbo inoshanda ye ribosome uye dzinoita sedzinobatsira kuchengetedza (kana kudzoreredza) kuungana kwakanaka kwe ribosome uko kwaizokanganiswa ne rRNA yakaderera. Izvi zvinoratidza kuti hunyanzvi hukuru hwe microsporidia ribosome hunoratidzika kunge hwakashanduka kuita kudiwa kwe buffer gene drift.
Zvichida izvi zvinonyatsoratidzwa nekusunga nucleotide, izvo zvisati zvamboonekwa mune zvimwe zvipenyu kusvika pari zvino. Chokwadi chekuti ma residues ekubatanidza nucleotide aripo mu microsporidia yakajairika, asi kwete mune mamwe eukaryotes, chinoratidza kuti nzvimbo dzinosunga nucleotide hadzisi nzvimbo chete dzakamirira kunyangarika, kana nzvimbo yekupedzisira yekuti rRNA idzorerwe muchimiro che nucleotides yega yega. Pane kudaro, nzvimbo iyi inoita sechinhu chinobatsira chaigona kunge chakashanduka mukati menguva dzakawanda dzekusarudza kwakanaka. Nzvimbo dzinosunga nucleotide dzinogona kunge dziri chibereko chekusarudza kwechisikigo: kana ES39L yaora, microsporidia inomanikidzwa kutsvaga muripo wekudzorera biogenesis ye ribosome yakakwana pasina ES39L. Sezvo nucleotide iyi ichigona kutevedzera ma molecular contacts eA3186 nucleotide mu ES39L, nucleotide molecule inova chivakwa che ribosome, iyo kubatana kwayo kunovandudzwa nekuchinja kwe eL30 sequence.
Nezvekushanduka kwemamorekuru ezvipembenene zvinopinda mumasero, chidzidzo chedu chinoratidza kuti masimba eDarwinian natural selection uye kushanduka kwemajini ekuora kwemajini hazvishande panguva imwe chete, asi zvinotenderera. Chekutanga, kushanduka kwemajini kunobvisa zvinhu zvakakosha zvebiomolecules, zvichiita kuti muripo udiwe zvikuru. Kana zvipembenene zvikagutsa chishuwo ichi kuburikidza neDarwinian natural selection ndipo chete apo macromolecules avo achava nemukana wekuvandudza hunhu hwavo hunoshamisa uye hutsva. Zvakakosha, kushanduka kwenzvimbo dzinosunga nucleotide muE. cuniculi ribosome kunoratidza kuti iyi pateni yekushanduka kwemamorekuru inorasikirwa nekuwana haingogumiri pakuderedza shanduko dzinokuvadza, asi dzimwe nguva inopa mabasa matsva zvachose pamacromolecules ezvipembenene.
Pfungwa iyi inoenderana nedzidziso yaSewell Wright yekufamba kwe equilibrium, iyo inoti hurongwa hwakasimba hwekusarudza kwechisikigo hunoganhurira kugona kwezvisikwa 51,52,53. Zvisinei, kana genetic drift ikakanganisa natural selection, drift idzi dzinogona kugadzira shanduko dzisiri dzoga dzinochinjika (kana kutokuvadza) asi dzinotungamira kune dzimwe shanduko dzinopa hutano hwakanaka kana chiitiko chitsva chebhayoloji. Rondedzero yedu inotsigira pfungwa iyi nekuenzanisira kuti mhando imwechete yekuchinja inoderedza kupeta uye kushanda kwebiomolecule inoita seyakanyanya kukonzera kuvandudzwa kwayo. Zvichienderana nemuenzaniso wekushanduka-shanduka unohwina-hwina, chidzidzo chedu chinoratidza kuti kuora kwegenome, kwagara kuchionekwa senzira yekuora, ndiyowo nzira huru yekuvandudza, dzimwe nguva uye pamwe kazhinji inobvumidza macromolecules kuwana mabasa matsva eparasite.