Wonk 'ubani ufunda ezinto eziphilayo, ezinto, ubunjineli yemfuza, kunye nenani kwezinye ulwazi olunxulumene, kungekudala emva koko, ubuza umbuzo: yintoni umsebenzi RNA polymerase? Le isihloko noko enobuzaza nangoku unexplored ngokupheleleyo, kodwa, nangona kunjalo, kuyaziwa ukuba kuya text njengenxalenye inqaku.
ulwazi jikelele
Kuyimfuneko ukuba ukukhumbula ukuba kukho RNA polymerase of eukaryotes kunye prokaryotes. Eyokuqala sahlulwe ngeentlobo ezintathu, nganye linoxanduva noshicilelo yemfuza iqela eyahlukileyo. Ezi enzyme zibaliwe kuba lula, njengoko polymerase RNA yokuqala, eyesibini, neyesithathu. Prokaryotes, isakhiwo apho non-nuclear, xa yayishicilelwe isebenza ngokungqinelana umzobo lula. Ngoko ke, ecacileyo, ukuba zifake ingcaciso kangangoko eukaryotes kuya kwenzeka ngayo. polymerases RNA iyafana ngokokwakheka. Kukholelwa ukuba ibe ngaphantsi kwe-10 neentsontelo polypeptide. Ngaloo ndlela RNA polymerase synthesizes 1 (Ukukhuphela) zofuzo apho kamva yaguqulelwa iiproteni ezahlukeneyo. Owesibini benza imfuza ekubhaleni, apho kamva yaguqulelwa njengeprotini. RNA polymerase 3 ubonisa enzayim ezizinzileyo ezahlukeneyo ephantsi ezinto ubunzima ukuba zinobuthakathaka ukuya alpha amatinu. Ke thina asenzanga isigqibo yintoni kanye le RNA polymerase! Ngoko wabiza enzayim bekwi Yindibanisela iimolekyuli acid ribonucleic. Ngengqiqo emxinwa kuqondwe le RNA polymerase DNA-abaxhomekeke, asebenza ngokwesiseko isizalo of deoxyribonucleic acid. Enzyme kubalulekile ukuba ukusebenza elide kunye ngempumelelo izinto eziphilayo. RNA polymerase inokufunyanwa kuzo zonke iiseli kunye iintsholongwane ezininzi.
Isahlulo kwi nkcukacha
Kuxhomekeka enganeno ukwakhiwa polymerases RNA bohlulwa babe ngamaqela amabini:
- KwiVangeli ebhalwe nguye ubalisa ekubhaleni inani elincinane zofuzo kwi genomes ezilula. Kuba ukusebenza kulo mzekelo ayifuni impembelelo entsonkothileyo yolawulo. Ngoko ke, apha ubhekisela zonke enzayim luqulathe enganeno elinye kuphela. Ngokomzekelo kunokubangela i RNA polymerase bacteriophage kunye mitochondria.
- Eli qela libandakanya onke RNA polymerase eukaryotic neentsholongwane, nto leyo kunzima amalungiselelo. Bathe ezihlelwe izakhiwo mnogosubedinichnye protein ukuba unako ukubhala amawaka ngezakhi ezahlukeneyo. Ngexesha ukusebenza, aba gene uphendule inani elikhulu imiqondiso yokulawula zifunyanwa imiba iiproteins kunye nucleotides.
Ezo division noshowo kwaye esebenza kakhulu kunokuba ezinemiqathango kunye lula meko.
Yintoni i-RNA polymerase I?
Baye fixed umsebenzi wemfundo of ezikhutshelweyo ephambili rRNA yemfuza, oko kukuthi, ukuba zibaluleke kakhulu. ZifunwaEzokugqibela zidweliselwe saziwa ngakumbi phantsi nokonyulwa 45S-RNA. ubude sabo 13 000 nucleotides. Ukusuka kuyo akhiwa 28-RNA, 18s-5.8S RNA-RNA. Ngenxa yokuba ukuba wadala transkriptor omnye kuphela, umzimba ufumana "isiqinisekiso" ukuba molekyuli ziya abunjwe wezixa ezilinganayo. Ngelo xesha linye indalo RNA uhamba ngqo nucleotides 7000 kuphela. Ezinye okotshiweyo into yokuthotywa isidima nucleus. Kwintsalela elikhulu enjalo kukholelwa ukuba kuyimfuneko ukuba nisaqala ukuyilwa ribosomes. Inani le polymerases xa iiseli abantu ephezulu endiza ngeenxa zonke uphawu kweeyunithi amawaka 40.
Indlela ecwangciswe ngayo?
Ngenxa yoko, sinawo polymerase RNA lokuqala (prokaryotes-isakhiwo iimolekyuli) uthathwa elungileyo. Kulo mzekelo, i enganeno enkulu, njengoko, eneneni, kwaye inani elikhulu kwezinye polypeptides eziphakamileyo ubunzima eziphilayo, kukho ngokucacileyo amathambeka distinguishable esebenza kunye zesakhiwo. Ngexesha ezinezakhi genes and ukumisela ubume babo zaseprayimari eziye zachongwa yi zizazinzulu evolutionarily iinxenye wolondolozo ngemixokelelwane. Ukusebenzisa ibinzana elungileyo, abaphengululi iye yenziwa uhlahlelo mutational evumela ukuba sithethe ngayo ukubaluleka esebenzayo domain ngamnye. Ukulungiselela le njongo, esebenzisa mutagenesis site-ngqo ukutshintsha imixokelelwane polypeptide ngamnye, yaye loo subunits acid acid ilungiswe kusetyenziswa kwindibano enqanda uhlahlelo elandelayo kwiipropati, ezo zifunyenwe kwi izakheko data. Kwaqondwa ukuba ngenxa yokuba umbutho wawo polymerase yokuqala RNA phambi alpha-amatina (into inetyhefu kakhulu, nto leyo ifunyenwe ukusuka okona sakuba) modem.
ukusebenza
Zombini lokuqala kunye RNA polymerase yesibini sinokubakho iifom ezimbini. Omnye wabo sinokwenza ukuba ziqalise noshicilelo ethile. Okwesibini - DNA-oxhomekeke RNA polymerase. Esi simo sengqondo esibonakaliswa ukusebenza likhulu lo msebenzi. Isihloko wafunda ngakumbi, kodwa ngoku siyazi ukuba kuxhomekeke kwizinto ukhutshelo ezimbini kubhekiselelwe kuwo SL1 kunye uBf. Ingakumbi yokugqibela - ukuba anxibelelane ngqo ekukhuthazeni, lo gama i-SL1 uBf ufuna khona. Nangona kuye ngokomfuniselo yasekwa ukuba DNA-abaxhomekeke RNA polymerase lukwazi ukuthatha inxaxheba noshicilelo kwi ubuncinane kwaye ngaphandle phambi yokugqibela. Kodwa ukusebenza eqhelekileyo kule ndlela uBf nangoku kuyimfuneko. Kutheni kunjalo? Ngokuphawulekayo kangaka kude usilele ukuseka unobangela wale yokuziphatha. Enye ingcaciso kakhulu zithandwa icebisa ukuba uBf Lomqulu uhlobo ivuselela rDNA Ukukhuphela xa ekhula kwaye ziphuhlisa. Xa uphumle isigaba kwenzeka, ngoko wahlala kobuncincane obufunwa nenqanaba lokwenziwa komsebenzi. A inxalenye imiba ukhutshelo akuyonto ibalulekileyo kuye. Apha ke kusebenza RNA polymerase. Umsebenzi weli enzyme ivumela ukuxhasa ukudlalwa "iibhloko zokwakha 'encinci umzimba, ngenxa apho rhoqo kwahlaziywa eminyaka.
Iqela lesibini enqanda
ukusebenza kwawo lilawulwa ibandla multiprotein abakhuthaza preinitsiatornogo entsonkothileyo kwiklasi yesibini. Amaninzi oku kuchazwe umsebenzi iiproteni ezikhethekileyo - activators. Njengoko isibonelo i TBP. It is ezihambisana izinto eziyinxalenye TFIID. Bona - ithagethi ngenxa p53, NF kappa B, njalo-njalo. impembelelo yawo kule nkqubo wolawulo nokubonelela okuthiwa coactivators. Imizekelo Gcn5. Kutheni kufuneka ezi iiprothini? Bakhonza amaqhoshana ukuba wenze impefumlelwano activators kunye zinto ke ezintsonkothileyo preinitsiatorny. Ukuze alungise umbhalo yenzekile, kufuneka ukuba izinto eziyimfuneko umqalisi. Nangona isibakala sokuba ezintandathu kubo, basebenzisane ngqo ekukhuthazeni isenokuba omnye kuphela. Kuba kwezinye iimeko kufuna entsonkothileyo eyenziweyo ye-Polymerase RNA yesibini. Ngaphezu koko, xa besenza ezi nkqubo ezikufutshane proximal iziqalelo - bengababini 50-200 kuphela ukusuka kwisiza apho ukhutshelo luqaliweyo. Bona ziqulathe ebonisa yokubopha kweziyi isilumeki.
iimpawu ezithile
Ngaba isakhiwo enganeno ye-enzayim ye imvelaphi ezahlukeneyo indima yabo ezisebenzayo kwi noshicilelo? Impendulo ngqo lo mbuzo akukho; kodwa bakholwa ukuba kusenokwenzeka positive. wakwenza njani oko kuchaphazela RNA polymerase? Imisebenzi enzyme isakhiwo esilula - uluhlu elilinganiselweyo ukubhalelwa yemfuza (okanye inxenye encinane). Imizekelo Yindibanisela RNA kwenziwa Okazaki iziqwenga. Le ekukhuthazeni ingakumbi ezo polymerases RNA iintsholongwane kunye phages kukuba enzyme abanini lwesakhiwo ilula kwaye zahlukahlukene. Oku kunokubonwa kwinkqubo ye DNA phindana ntsholongwane. Nangona singakwazi kuqwalasela oku: isakhiwo esimbaxa xa efunda genome T nkqu phage, ngexesha uphuhliso, kwaye kwaqatshelwa ukuba waphinda isenza i phakathi kwamaqela awohlukeneyo gene ukhutshelo, kwafunyaniswa ukuba complex esetyenziselwa le host RNA polymerase. Oko kukuthi, i-enzayimi elula kwiimeko ezinjalo akukho wayenga. Oku kuthetha ukuba inani lweziqhamo:
- RNA polymerase of eukaryotes neentsholongwane kufuneka abe nako ukuqonda bawo ezahlukeneyo.
- Kuyimfuneko ukuba enzyme unalo impendulo ethile ezahlukeneyo iiproteni-nabalawuli.
- RNA polymerase kufuneka ukwazi ukutshintsha ukuqatshelwa ingakumbi ukulandelelana nucleotide DNA template. Ukuze wenze oku, sebenzisa iintlobo ngeentlobo effectors protein.
Oku kulandela imfuneko umzimba ukuze "isakhiwo" izinto ezongezelelweyo. Iiproteni zinceda akhuphele entsonkothileyo RNA polymerase ukwenza ngokupheleleyo ngaphandle imisebenzi yayo. Oku kusebenza, kuba ezininzi, i-enzayim isakhiwo enzima, apho amathuba asebenzisa inkqubo ebanzi inkcazelo yemfuza. Ngenxa yeengxaki ezahlukahlukeneyo, sinako ukubona uhlobo lwesakhiwo kuluhlu RNA polymerase.
wenza njani inkqubo umbhalo?
Ingaba kukho isakhi onoxanduva ngokusebenzisana polymerase RNA? Ukuze ukuqala Ukuloba: inkqubo eukaryotes ithatha indawo ngumongo. Xa prokaryotes, ayajika ngaphakathi silwanyana. Ubudlelwane phakathi polymerase isimiso esisiseko noshowo a iimolekyuli lokukhwela ngamnye ezisebenzisanayo. Ngezingxaki yentsebenziswano sinokuthi DNA nje template yaye akatshintshi ngexesha tumbuluxiwa. Ekubeni DNA transcriptase ngokupheleleyo, into esiqiniseke, ukuba isakhi ethile unoxanduva le Polymer unokuba, kodwa kuya kubakho ixesha elide kakhulu. Asimele silibale ukuba iDNA iqulethe 3.1 billion iintsalela nucleotide. Ngoko ke, kungakuhle ukuba bathi ngohlobo ngalunye RNA idibana DNA yayo. Kuba ukuhamba indlela polymerase kufuneka amandla kunye ribonukle-ozidtrifosfato substrates. Ukuba naliphi na akhiwa 3 ', iibhondi 5'-phosphodiester phakathi ribonukleozidmonofosfatami. Yomoya RNA yokuqaphela iqala ulandelelwano ezithile DNA (bawo). Le nkqubo uphelisa kumaziko ukupheliswa (ukupheliswa). Isiza, nto leyo ebandakanyekileyo apha kuthiwa transcriptional. Xa eukaryotes, kukho ngokuqhelekileyo na gene omnye kuphela, lo gama prokaryotes kwakhona ilifa amaqhekeza ezininzi lwe khowudi. transcriptional nganye indawo uninformative. Bona ibekwe ulandelelwano nucleotide ethile ezisebenzisana ngayo izinto transcriptional yemimiselo zikhankanywe ngasentla.
Bacteria RNA polymerase
Ezi Cya omnye enzyme inoxanduva Yindibanisela mRNA, rRNA kunye tRNA. I-avareji polymerase molecule abe nama-5 subunits. Ezimbini kwezi bakhonza njengento ebophelelayo amalungu enzyme. Enye enganeno inxaxheba nokuqaliswa yokuqaphela. Kukwakho icandelo enzyme nonspecific lonxibelelwano DNA. Kwaye enganeno yokugqibela sele ukonakalisa polymerase RNA ngendlela esebenzayo. Kuyaphawuleka ukuba molekyuli enzyme azikho i "ezamahala 'siwele xa kukho icytoplasm iintsholongwane. Xa zisetyenziswa polymerases RNA, ngoko bathe bandibopha imimandla DNA non-ezithile yaye ukulinda de kube ekukhuthazeni esebenzayo ivulwa. A bit uyaphazamiseka nesihloko, kufuneka kuthiwe iintsholongwane Kulula kakhulu ukufunda iiprothini kunye nefuthe lazo acid polymerase ribonucleic. Ingakumbi sikuvumela ukuba asebenzise inkanuko okanye inhibition eziqalelo ngamnye. Ngenxa izinga zabo ukuzala eliphezulu kunokuba ngokukhawuleza ukufumana isiphumo oyifunayo. Yeha, isifundo babantu kuqhutywa elinjalo okukhawulezayo isantya sibulela ukuba iyantlukwano yethu zesakhiwo.
RNA polymerase "babanjwa" ngeendlela ezahlukahlukeneyo?
Oko kuza ku kwisigqibo alandise nqaku. Ingqalelo ephambili yahlawulwa eukaryotes. Kodwa kusekho archaea kunye neentsholongwane. Ngoko ufuna ukuhlawula isuntswana ingqalelo kwaye ezi ntlobo ebomini. Umsebenzi ebalulekileyo Archean kukho elinye iqela kuphela polymerases RNA. Kodwa ke iyafana kakhulu iimpahla zazo kunye nemibutho eukaryotes ezintathu. Izazinzulu ezininzi ziye zacebisa ukuba oko sinokubona wayeyindalo okunene ukhokho yokuzivelela of polymerases zizodwa. Kwakhona umdla, kwaye ubume iintsholongwane. Njengoko kubhaliweyo ngaphambili, hayi zonke ezi zinto ziphilayo babe polymerase zabo. Kwaye apho ke kukuthi, enganeno enye. Kukholelwa ukuba i-enzayim viral ezithathwe polymerases DNA, endaweni izakhiwo RNA ezintsonkothileyo. Nangona ngenxa kwiyantlukwano eli qela ezincinane ukuphunyezwa ezahlukeneyo edibana indlela elinikiweyo zebhayoloji.
isiphelo
Awu, abantu okunene akakabi nalo ulwazi vsoy kuyimfuneko olufunekayo ukuqonda zofuzo. Nokuba kuphela akwazi ukukwenza! Phantse zonke izifo ababangela nje zofuzo - oku kusebenza ngokukodwa iintsholongwane onika rhoqo thina iingxaki zizifo njalo njalo. Izifo ezona isisifo esibi - nobona, enyanisweni, zixhomekeke ngqo okanye ngokungathanga ngqo kwi zofuzo zabantu. Xa sifunda siyiqonde ngokwabo yaye iya kusebenza olu lwazi ukuze kuxhamle inani elikhulu iingxaki kunye nezifo ziya siphele khona. Ngoku yinto elidlulileyo, izifo ezininzi ngaphambili ezoyikekayo ezifana esifo, sibetho. Ukufumana ukulungele ukuya uqilikwane, unkonkonko. Kodwa musa uphumle, kuba sijamelene ezinenani nangakumbi lemingeni ezahlukeneyo kufuneka ukuba ufumane impendulo. Kwaye uya kufunyanwa, ngoba izakuba ukwenza njalo.