遗传学精要—谢雄泽.ppt

,The termination of translation,谢雄泽,农学1003班,A01100070,翻译的终止,Key words,Key words,polypeptide ,plpeptad n. 生化 多肽，缩多氨酸 E.coli i:kulai n.大肠(杆)菌 eukaryote jukrt n. 真核生物 prokaryote prkrt; -t n.原核生物 synthetic snetk adj. 综合的；合成的，人造的 n. 合成物 ribosome rab()sm n.生化 核糖体；生化 核蛋白体 dissociate dsoet vt. 游离；使分离；分裂 vi. 游离；分离；分裂 transpeptidase trnspptdez n. 转肽酶 esterase estrez n. 生化 酯酶 cytoplasm sat()plz()m n. 细胞 细胞质,2019/6/6,Topic,Translation ends when a termination codon enters the A site. Release factors enter the A site and cause release of the polypetide. In E.coli RF1,2 and 3 cause termination. In eukaryotes a single protein ,eRF,is involved. Following termination the ribosome dissociates and the mRNA is released.,当终止密码子进入核蛋白体A部位的时候翻译结束。释放因子进入A部位，多肽被释放出来。在大肠杆菌中，释放因子RF1，RF2，RF3导致终止的发生。在真核生物中，则是一种蛋白质eRF与翻译的终止有关。伴随着终止的发生，核蛋白体分离，mRNA被释放出来。,They are the codon that cant be recognized normally by any tRNA, but can be combined by special protein to cause a new synthetic peptide chain released from translation machines. They are UAG, UGA and UAA. 任何的tRNA都不能正常识别，但是可以被特别的蛋白质结合并引起新合成的肽链从翻译机器上释放的密码子。他们分别是，和。,Termination codon 终止密码子,What is the termination codon？,The protein factor is related to termination called release factor. It can identify protein which termination codon cause complete peptide chains and ribosomes release from mRNA. 与终止相关的蛋白因子称为释放因子。它可以识别终止密码子引起完整的肽链和核糖体从mRNA上释放的蛋白质。,Prokaryotes(原核生物) release factor：RF-1，RF-2，RF-3 . Eukaryotes(真核生物 )release factor：eRF.,Release factor 释放因子,The function of release factor: 一：Identify termination codon,such as, RF-1 recognize UAA、UAG；RF-2 recognize UAA、UGA. 识别终止密码，如RF-1特异识别UAA、UAG；而RF-2可识别UAA、UGA。 二: Make transpeptidase turn into esterase activity, catalytic peptide acyl transfer to water molecule-OH to release peptide chain from the ribosome. 诱导转肽酶改变为酯酶活性，相当于催化肽酰基转移到水分子OH上，使肽链从核蛋白体上释放。,A位：氨基酰位 (aminoacyl site),P位：肽酰位 (peptidyl site),E位：排出位 (exit site),mRNA通道,The ribosome structure mode during the course of translation In the prokaryotes 原核生物翻译过程中核蛋白体结构模式,The function of each binding sites： 每个结合位点的功能 A site：Combine with new incorporation of ammonia acyl tRNA. 结合新掺入的氨酰-tRNA P site：Combine with extension of peptide acyl - tRNA. 结合延伸中的肽酰-tRNA E site：Combine with the released tRNA after peptide acyl transfer. 结合肽酰转移后即将释放的tRNA,The process of termination 终止的过程,Picture here,Text heere,Termination codon appear. 终止密码子出现,Release factors enter the A site and cause release of the polypetide. 释放因子与核蛋白体A部位结合，多肽被释放出来。,多肽,The ribosome dissociates and the mRNA is released. 大小亚基分离，mRNA被释放出来。,大亚基,小亚基,mRNA,The process of translation termination in prokaryotes: 原核生物翻译终止的过程,RF,肽链合成的终止动态演示,2019/6/6,Summary,Translation of termination appeares in the process of protein translation in the specific period. Its realization needs mRNA, tRNA, subunit, releasing factor and a series of factors combine specifically in the cytoplasm. Translation of termination not only mark the new peptide synthesise, at the same time，also mark the new protein synthesise. It has a very important biological significance. 翻译的终止是蛋白质翻译过程中出现的