参与原核生物dna复制的酶类和蛋白质

《参与原核生物dna复制的酶类和蛋白质》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、参与原核生物DNA复制的酶类和蛋白质EnzymesandProteinsInvolvedinDNAReplicationinProkaryotes高方远马欣荣康海岐DNAreplication(bacteria)InitiationElongationTerminationDaughterDNApartition*theoriginofreplicationisdefined*replicationbubble.*Replicationfork*Unidirectionalorbidirecti

2、onal.OriginsFigure13.9Theleadingstrandissynthesizedcontinuouslywhilethelaggingstrandissynthesizeddiscontinuously.Elongation(semidiscontinuous)termination参与DNA复制的酶类1、DNA聚合酶2、DNA引发酶（DNAprimase）3、DNA连接酶4、与DNA几何学性质相关的酶IpolAmajorrepairenzymeIIpolBminorrep

3、airenzymeIIIpolCreplicaseIVdinBSOSrepairVumuC、DSOSrepairDNApolymerasesinE.coliDNAPolymeraseIDNApolymerase3’5’exonuclease5’3’exonucleaseFigure13.8ThecatalyticdomainofaDNApolymerasehasaDNA-bindingcleftcreatedbythreesubdomains.Theactivesiteisinthepalm.P

4、roofreadingisprovidedbyaseparateactivesiteinanexonucleasedomain.Figure13.7CrystalstructureofphageT7DNApolymerasehasarighthandstructure.DNAliesacrossthepalmandisheldbythefingersandthumb.PhotographkindlyprovidedbyCharlesRichardsonandTomEllenberger.Figu

5、re13.5Nicktranslationreplacespartofapre-existingstrandofduplexDNAwithnewlysynthesizedmaterial.DNAPolymeraseISubunitcompositionofE.coliDNApolymeraseIIIholoenzymesubunitmolecularmassfunctionsubassemblies(KDa)α129.9DNApolymeraseε27.53’5’exonucleasecoreθ

6、8.6stimulatesexonucleaseι71.1dimerizescorePolIII’bindsγcomplexγ47.5bindsATPδ38.7bindstoβPolIIIδ’36.9bindstoγandδγcomplexχ16.6bindstoSSBDNA-dependentψ15.2bindstoχandγATPaseβ40.6slidingclampE.coliPolIIIBeta-subunitFigure13.18DNApolymeraseIIIholoenzymea

7、ssemblesinstages,generatinganenzymecomplexthatsynthesizestheDNAofbothnewstrands.Fig.1. ModelofSOStranslesionreplicationbyDNApolymeraseV. ThetwoDNAstrandsareshownasgreenlines,andthereplication-blockinglesionisrepresentedbytheredrectangle.Thethreemajor

8、stepsinTLRarepre-initiation(2),inwhichtheRecAnucleoproteinfilamentsassembles;initiation(3and4),whichinvolvesbindingofpolVtotheprimer-templateandloadingofthe subunitclamp;andlesionbypassbypolVholoenzyme(5).SSBissuggestedtohelpindisplacingRecAfromDNAbo