英汉对照分子生物学导论-Chapter-6课件

1、1 / 56Chapter 6 Translation / 翻译翻译2 / 56Chapter 6 Translation / 翻译翻译6.1 The Genetic Code6.2 Mechanism of Translation in Prokaryotes6.3 Translation in Eukaryotes6.4 tRNA Structure and Wobble6.5 Experiments6.1 遗传密码6.2 原核生物翻译机理6.3 真核生物翻译6.4 tRNA结构与摇摆6.5 实验研究3 / 566.1 The Genetic Code / 遗传密码遗传密码Translat

2、ion: synthesis of a protein using an mRNA as the template.Transcription4 / 56 tRNA: the converter5 / 56 tRNA: the converter6 / 564 bases vs. 20 amino acidsUCAG GlyAla Ile Leu Met Phe Trp Pro Val SerThr Asn Gln Cys Tyr AspGlu Arg HisLys7 / 561 base 1 amino acidUCAG GlyAla Ile Leu Met Phe Trp Pro Val

3、SerThr Asn Gln Cys Tyr AspGlu Arg HisLys8 / 562 bases 1 amino acidUUUCUAUGGlyAla Ile Leu Met Phe Trp Pro Val SerThr Asn Gln Cys Tyr AspGlu Arg HisLysCUCCCACGAUACAAAGGUGCGAGG9 / 563 bases 1 amino acid10 / 56The genetic code / 遗传密码遗传密码11 / 566.2 Mechanism of Translation in Prokaryotes原核生物翻译机理原核生物翻译机理6

4、.2.1 Initiation / 起始6.2.2 Elongation / 延伸6.2.3 Termination / 终止12 / 56Composition of prokaryotic ribosome原核生物核糖体的组成原核生物核糖体的组成13 / 566.2.1 Initiation / 起始起始IF-1DissociationIF-3No reassociationSeparation of 30S and 50S subunits14 / 56SD sequence: the translation start signal15 / 5616S rRNA3 end16 / 56

5、The 30s initiation complex30S起始复合体起始复合体The collection of the 30S subunit, the mRNA, and the initiator tRNA is called the 30S initiation complex.17 / 56The initiator tRNA18 / 56The 70S initiation complex19 / 56The 70S ribosome20 / 566.2.2 Elongation / 延伸延伸1) tRNA entering2) Peptidyl transfer3) Transl

6、ocation4) tRNA leaving21 / 561) tRNA entering / tRNA进入进入22 / 562) Peptidyl transfer / 肽基转移肽基转移23 / 563) Translocation / 移位移位24 / 564) tRNA leaving / tRNA离开离开25 / 56Elongation factors / 延伸因子延伸因子Weaver, Molecular Biology, Chapter 1826 / 56Elongation factors / 延伸因子延伸因子Weaver, Molecular Biology, Chapter

7、 1827 / 566.2.3 Termination / 终止终止Translation terminates when ribosome reaches a stop codon, because there is no tRNA being able to bind to the stop codon.28 / 56Now showingTranslation: the three stepsFile: biophoto7 Introduction to Genetic Analysis Translation: the three steps of translation (5)29

8、/ 566.3 Translation in Eukaryotes真核生物翻译真核生物翻译Composition of eukaryotic ribosome真核生物核糖体的组成30 / 56Differences in Translation Initiation翻译起始的不同点翻译起始的不同点1) Initiator tRNA / 其始tRNA2) The scanning model / 扫描模型31 / 561) Initiator tRNA / 其始其始tRNACAUAAnticodonfMet-tRNAfMet Formyl Met A C C5 AC AG CA* Alkylat

9、ed adenosineAnticodonMet-tRNAMet Met A C C5 AG CG CAG-引自：Turner, P. C. et al.分子生物学精要速览（影印版），科学出版社，1999，p.249CAUProkaryotic initiator tRNAEukaryotic initiator tRNA32 / 56Prokaryotic initiator tRNA 70S ribosome33 / 56Eukaryotic initiator tRNA 80S ribosomeCH334 / 56Yeast 80S ribosomeFile: Yeast 80S rib

10、osome 1S1I.val 35 / 562) The scanning model / 扫描模型扫描模型Prokaryotes:SD sequenceEukaryotes:Scanning model36 / 56The scanning model / 扫描模型扫描模型37 / 56Translation initiated by entering IRES site directly通过直接进入通过直接进入IRES位点启动翻译位点启动翻译IRES: internal ribosome entry sequence38 / 56Picornavirus / 小核糖核酸病毒小核糖核酸病毒

11、www.uniklinikum-giessen.de/./res_ires.htm Internal entryAUG39 / 56Translation initiation in eukaryotes (1/4)eIFeukaryotic initiationfactor40 / 56Translation initiation in eukaryotes (2/4)41 / 56Translation initiation in eukaryotes (3/4)42 / 56Translation initiation in eukaryotes (4/4)43 / 566.4 tRNA

12、 Structure and WobbletRNA结构与摇摆结构与摇摆44 / 566.4.1 Anti-codons / 反密码子反密码子45 / 56Three-dimensional structure of a tRNA46 / 56Aminoacyl-tRNA synthetase: a kind of enzyme that can recognize a tRNAs anticodon and match it with the correct amino acid. Aminoacyl-tRNA synthetase 氨酰氨酰tRNA合成酶合成酶47 / 56Aminoacyl

13、-tRNA synthetase53mRNACodon48 / 56Show 3D: synthetase-tRNA complexFile: E coli Thr-tRNA Synthetase Complex 1QF6.valAnti-codonAmino acid49 / 566.4.2 Wobble / 摇摆摇摆50 / 56Wobbling is possiblemRNAtRNADNA555551 / 56Wobbled base pairsBase at the first positionin the anticodonBases at the third positionin the codon U A, GG C, UI A, U, CTable 6.2 Allowed base pairings from wobble hypothesis表表6.2 摇摆假说允许的碱摇摆假说允许的碱基配对基配对52 / 56Wobbled base pairs53 / 566.5 Experiments / 实验研究实验研究6.5.1 Deciphering the genetic code 破译遗传密码6.5.2 Direc