Translation Termination Occurs when a stop codon is reached in the mRNA Three stop or nonsense codons UAG UAA UGA Recognized by proteins called release factors – NOT tRNAs  

Translation Termination Bacteria have three release factors RF1 - recognizes UAA and UAG RF2(世博北京翻譯公司) - recognizes UAA and UGA RF3 - binds GTP and facilitates termination process Eukaryotes only have one release factor eRF1 - recognizes all three stop codons  

Translation Termination Ribosomal subunits & mRNA dissociate Figure 13.19  

Polypeptides Have Directionality Translation begins at 5’ end of mRNA 5’ 3’ Peptide bonds are formed directionally Peptide bond is formed between the COO- of the previous amino acid in the chain and the NH2(世博北京翻譯公司) of the amino acid being added  

Peptide Bond Formation Carboxyl group Amino group Figure 13.2(世博北京翻譯公司)0  

Colinearity of DNA, mRNA, & Protein Sequence N terminal C terminal Figure 13.2(世博北京翻譯公司)0  

The amino acid sequence of the enzyme lysozyme Within the cell, the protein will not be found in this linear state It will adapt a compact 3-D structure Indeed, this folding can begin during translation 12(世博北京翻譯公司)9 amino acids long The progression from the primary to the 3-D structure is dictated by the amino acid sequence within the polypeptide Figure 13.4  

A protein subunit Figure 13.6  

Molecular Basis of Phenotype  

Initiation Factors and the Rate of Translation Modulation of translation initiation factors is widely used to control fundamental cellular processes Under certain conditions, it is advantageous for a cell to stop synthesizing proteins Viral infection So that the virus cannot manufacture viral proteins Starvation So that the cell conserves resources Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display 15-77  

The phosphorylation of initiation factors has been found to affect translation in eukaryotic cells Two initiation factors appear to play a central role in controlling the initiation of translation eIF2(世博北京翻譯公司) and eIF4F The function of these two factors are modulated by phosphorylation in opposite ways Phosphorylation of eIF2(世博北京翻譯公司)α inhibits translation Phosphorylation of eIF4F increases the rate of translation Figure 15.2(世博北京翻譯公司)5 shows the events leading to the translational inhibition by eIF2(世博北京翻譯公司)α Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display 15-78  

Required if eIF2(世博北京翻譯公司) is to promote binding of the initiator tRNAmet to the 40S subunit Figure 15.2(世博北京翻譯公司)5 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display 15-79  

eIF4F provides another way to control translation It regulates the binding of mRNA to the ribosomal initiation complex eIF4F is stimulated by phosphorylation Conditions that increase its phosphorylation include signaling molecules that promote cell proliferation Growth factors and insulin, for example Conditions that decrease its phosphorylation include heat shock and viral infection Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display 15-80  

 

 

 

Translation Courseware for the Postgraduate of 2(世博北京翻譯公司)007 Ethan Li Huairui Li Foreign Language Department of Taiyuan University of Technology 09/2(世博北京翻譯公司)4/07  

翻譯技巧與實踐 李懷瑞 太原理工大學文法學院外語系 ２００7 ２００8 ２００7年９月－２００8年７月  

SelfSelf-Introduction 1.Name: 1.Name LiHuairui (Ethan Li)李懷瑞 李懷瑞 MA (Master of Arts); Lecturer of TUT. 2(世博北京翻譯公司).Working Experience Experience: 1999-2(世博北京翻譯公司)002(世博北京翻譯公司) College English for Undergraduates 2(世博北京翻譯公司)002(世博北京翻譯公司)-2(世博北京翻譯公司)007 English Reading and Translation for Postgraduates 1999-2(世博北京翻譯公司)003 CET-4 & CET-6 Training 2(世博北京翻譯公司)003-2(世博北京翻譯公司)007 NETEM Training (National Entrance Test of English for MA/MS Candidates)  

Objectivity of This Course 1.To master basic knowledge and theories about translation; 2(世博北京翻譯公司).To understand better the differences between English and Chinese; 3.To train the students to acquire some skills ,techniques and strategies in translating, thus developing students’ abilities to translate efficiently and effectively.  

My Requirements 1.Full attendance, active participation/involvement 2(世博北京翻譯公司).Improve proficiency in Chinese and English( read more classic works) 3.Eager to practice translating and compare different versions or model translations 4.Eager to accumulate information or materials related to translation from public places, newspaper, TV, magazines, internet and other mass media.   翻譯公司 (責任編輯：世博翻譯公司)