英汉对照分子生物学导论 Chapter 3 Transcription in Prokaryotes

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1、Chapter3/第3章Chapter3TranscriptioninProkaryotes:MechanismandRegulation3.1WhyUseanRNAIntermediate?3.2MechanismofTranscription3.3RegulationofGeneExpressioninProkaryotes3.4Experiments第3章原核生物转录：机理与调控3.1为什么使用RNA作为中间物？3.2转录机理3.3原核生物基因表达调控3.4实验研究3.1WhyUseanRNAintermediate?3.1为什么使用RN

2、A作为中间物？ChromosomesarelargeandcomplexLowefficiency!DNAProteinRibosomeDNAmustbestableeOnemRNAmanyproteinsMoreopportunitiesforregulationChapter3Chapter43.2MechanismofTranscription3.2转录机理3.2.1Promoters/启动子−10boxand−35boxCCAGGCTTTACACTT---CGTATGTTGTGTGGAATTCTTTTTGATGCAATT---ACTAT

3、AATAGACAGGGTAGGCGGTGTTGACATA---GTGATACTGAGCACATCA-35box-10box+1Consensussequence/共有序列CCAGGCTTTACACTT---CGTATGTTGTGTGGAATTCTTTTTGATGCAATT---ACTATAATAGACAGGGTAGGCGGTGTTGACATA---GTGATACTGAGCACATCA-35box-10box+1TATAATTTGACAConsensussequencesConsensussequence:ageneralizedsequence

4、fromwhichmostactualsequencesdifferverylittleornotatall.（共有序列：一种普遍的序列，大多数实际的序列与它相差很小或完全相同。）3.2.2RNAPolymerase/RNA聚合酶Coreenzymevs.HoloenzymeHoloenzymestartstranscriptionatpromotersCoreenzymestartstranscriptionatrandomCatalyticareaofRNApolymerase3.2.3TranscriptionMechanism3.2.3

5、转录机理Initiation/起始Elongation/延伸Termination/终止1.Initiation/起始Step1Step2Initiation/起始Step3Step42.Elongation/延伸TranscriptionbubbleThepolymerizationreaction聚合反应RNAsynthesis:5’→3’Proofreading/校正UCRemoveUAddCNowshowingTranscriptionFile:biophoto7LifeTranscription.(5’)3.Termination

6、/终止Intrinsictermination内在型终止ρ-dependentterminationρ依赖型终止Intrinsictermination/内在型终止Basepair/碱基对ρ-dependenttermination/ρ依赖型终止RhoproteinsX-RayCrystalStructureOfRhoprotein[MMDBID:24381]NowshowingBacterialTranscriptionFile:biophoto7Genetics:AConceptualApproachBacterialtranscrip

7、tion(6’).3.3Regulationofgeneexpressioninprokaryotes3.3原核生物基因表达调控3.3.1CoordinateRegulation3.3.2TheLacOperon3.3.3TheTrpOperon3.3.4Ara&GalOperons3.3.1协同调控3.3.2乳糖操纵子3.3.3色氨酸操纵子3.3.4阿拉伯糖与半乳糖操纵子Regulationofgeneexpression基因表达调控ConditionARegulationofgeneexpression基因表达调控ConditionB3.

8、3.1CoordinateRegulation协同调控Operator操纵基因PolycistronicmRNA多顺反子mRNAPolycistron