分子生物学第七章翻译课件.pptxVIP

Topic 8 Antibiotics (抗生素) and translation 10/17/202 3 1 n Antibiotics inhibit cell division by blocking specific steps in translation —a powerful tool to fight disease n Targets of many antibiotics are translational machinery 10/17/202 3 2 10/17/202 3 Overview of the events of translation Termination Elongation Initiation 3 氯霉素 链霉素 10/17/202 3 红霉素 四环素 4 氯霉素 Molecular target: peptidyl transferase reaction center of 50S subunit Inhibit peptidyl transferase reaction specifically 10/17/202 3 5 Molecular target: A site of 30S subunit Inhibit aminoacylated-tRNA binding to A site 10/17/202 3 6 n In addition to medical benefits, antibiotics can play important role in research for understanding the function of translational machinery 10/17/202 3 7 Puromycin (嘌呤霉素) 3 10/17/202 Puromycin resembles the aminoacylated-tRNA, so it can bind to the A site of ribosome 8 10/17/202 3 9 Puromycin (嘌呤霉素) 肽酰嘌呤霉素 (peptidyl- puromycin) Puromycin 10/17/202 3 10 nPuromycin (嘌呤霉素) causes3 polypeptide synthesis to terminate prematurely 10/17/202 10/17/202 Release of peptidyl-puromycin from ribosome 11 Example I: nUse puromycin to study the peptidyl transferase reaction and prove that ribosome is a ribozyme(核酶) Use puromycin to explore the translational mechanism: 3 3 10/17/202 12 nBasic conception: what is peptidyl transferase reaction? 10/17/202 3 13 Peptidyl transferase reaction (肽酰转移酶反应) peptide bond N-terminal terminal 10/17/202 3 New - C 14 10/17/202 Raise scientific question about peptidyl transferase reaction (提出科学问题) n Which part of ribosome is responsible for peptidyl transferase reaction? (50S subunit or 30S subunit?) 15 3 Next question: rRNA or protein is responsible for peptidyl transferase reaction? 10/17/202 3 16 How to answer the scientific question(解决科学问题) Establish a good model Design the elegant experiment Analyze the experimental results Answer the scientific q