rokaryotic gene regulation：原核基因表達(dá)調(diào)控-文庫吧
2024-12-28 08:18 本頁面
【正文】 tune its metabolism to the changing environment and food sources ? This metabolic control occurs on two levels: – Adjusting activity of metabolic enzymes – Regulating genes that encode metabolic enzymes LE 1820 Regulation of enzyme activity Regulation of enzyme production Enzyme 1 Regulation of gene expression Enzyme 2 Enzyme 3 Enzyme 4 Enzyme 5 Gene 2 Gene 1 Gene 3 Gene 4 Gene 5 Tryptophan Precursor Feedback inhibition Copyright 169。 2022 Pearson Education, Inc. publishing as Benjamin Cummings Operons: The Basic Concept ? In bacteria, genes are often clustered into operons, posed of – An operator, an “onoff” switch – A promoter – Genes for metabolic enzymes ? An operon can be switched off by a protein called a repressor ? A corepressor is a small molecule that cooperates with a repressor to switch an operon off LE 1821a Promoter Promoter DNA trpR Regulatory gene RNA polymerase mRNA 3? 5? Protein Inactive repressor Tryptophan absent, repressor inactive, operon on Polycistronic* mRNA trpE trpD trpC trpB trpA Operator Start codon Stop codon trp operon Genes of operon E Polypeptides that make up enzymes for tryptophan synthesis D C B A 5? * = mRNA carries the information of several genes, which are translated into several proteins LE 1821b_1 DNA Protein Tryptophan (c
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