2021/1/21 Questions addressed in this chapter a What are the main challenges of translation and how do organisms overcome them? a What is the organization of nucleotide sequence information in mRNA? What is the structure of trnas and how do aminoacyl tRNa synthetases recognize and attach the correct amino acids to each tRNA? how does the ribosome orchestrate the translation process?
2021/1/21 7 Questions addressed in this chapter: ◼ What are the main challenges of translation and how do organisms overcome them? ◼ What is the organization of nucleotide sequence information in mRNA? ◼ What is the structure of tRNAs, and how do aminoacyl tRNA synthetases recognize and attach the correct amino acids to each tRNA? ◼ How does the ribosome orchestrate the translation process?
2021/1/21 Translation extremely costs In rapid growing bacterial cells protein synthesis consumes 80% of the cells energy a50% of the cell's dry weight Why?
2021/1/21 8 Translation extremely costs In rapid growing bacterial cells, protein synthesis consumes ◼ 80% of the cell’s energy ◼ 50% of the cell’s dry weight Why?
2021/1/21 The main challenges of translation a The genetic information in mRNa cannot be recognized b amino acids a The genetic code has to be recognized by an adaptor molecule(translator, and this adaptor has to accurately recruit the corresponding amino acid
2021/1/21 9 The main challenges of translation ◼ The genetic information in mRNA cannot be recognized by amino acids. ◼ The genetic code has to be recognized by an adaptor molecule (translator), and this adaptor has to accurately recruit the corresponding amino acid
2021/1/21 Translation machinery 1.mRNAS(N5% of total cellular RNA) 2. tRNAS(~15%) 3. aminoacyl-tRNA synthetases (氨酰tRNA合成酶) 4. ribosomes( 100 proteins and 3-4 rRNAs~80%) 10
2021/1/21 10 Translation machinery 1. mRNAs (~5% of total cellular RNA) 2. tRNAs (~15%) 3. aminoacyl-tRNA synthetases (氨酰tRNA合成酶) 4. ribosomes (~100 proteins and 3-4 rRNAs--~80%)
Outline 2021/1/21 Topics 1-4: Four components of translation machinery T1-mRNA: T2-tRNA: T3-Attachment of amino acids to tRNa (aminoacyl- RNA synthetases); T4-The ribosome Topic 5-6: Translation process. T5-initiation; T6-elongation; T7- termination Topic 8: Translation-dependent regulation of mRNA and protein stability
2021/1/21 11 Outline Topics 1-4: Four components of translation machinery. T1-mRNA; T2-tRNA; T3-Attachment of amino acids to tRNA (aminoacyltRNA synthetases); T4-The ribosome Topic 5-6: Translation process. T5-initiation; T6-elongation; T7- termination. Topic 8: Translation-dependent regulation of mRNA and protein stability