上降充通大粤 .5.1 Mechanism of Repression:Repressor and corepressor阻遏物与共阻遏物 arg Promoter)arg Operator argC argB argH RNA polymerase Transcription proceeds (a) Repressor 2012 Pearson Education,Inc. Transcription of the operon occurs because the repressor is unable to bind to the operator..阻遏蛋白不能与操纵基因结 合，所以操纵子可转录 Chen Feng,Shanghai Jiao Tong University
Chen Feng, Shanghai Jiao Tong University 8.5.1 Mechanism of Repression: Repressor and corepressor 阻遏物与共阻遏物 Transcription of the operon occurs because the repressor is unable to bind to the operator.阻遏蛋白不能与操纵基因结 合,所以操纵子可转录
arg Promoter)arg Operator argC argB argH RNA Corepressor polymerase (arginine) Transcription blocked (b) Repressor 2012 Pearson Education,Inc. (b)After a corepressor binds to the repressor,the repressor binds to the operator and blocks transcription; 共阻遏物的作用 In argCBH operon the repressor would be the arginine repressor and the corepressor would be arginine
(b) After a corepressor binds to the repressor, the repressor binds to the operator and blocks transcription; 共阻遏物的作用 In argCBH operon the repressor would be the arginine repressor and the corepressor would be arginine
上游充通大淫 SHANGHAI JIAO TONG UNIVERSITY arg Promoterarg Operator argc argB argH RNA polymerase →→→ Transcription proceeds (a) Repressor arg Promoter)arg Operator argc argB argH RNA Corepressor polymerase (arginine) Transcription blocked (b) Repressor 2012 Pearson Education.Inc. The process of enzyme repression
The process of enzyme repression Chen Feng, Shanghai Jiao Tong University
上降充通大粤 HANGHAI JIAO TONG UNIVERSITY 5.2 Mechanism of Induction:Inducer and repressor诱导物与阻遏蛋白 lac Promoter lac Operator lacZ lacY lacA RNA polymerase U Transcription blocked Repressor (a) 2012 Pearson Education.Inc. A repressor protein binds to the operator region and blocks the action of RNA polymerase.阻遏蛋白可与操纵基 因结合而阻断RNA聚合酶的行为 Chen Feng,Shanghai Jiao Tong University
Chen Feng, Shanghai Jiao Tong University 8.5.2 Mechanism of Induction: Inducer and repressor 诱导物与阻遏蛋白 A repressor protein binds to the operator region and blocks the action of RNA polymerase.阻遏蛋白可与操纵基 因结合而阻断RNA聚合酶的行为
FLASH 1:lac operon lac Promoter lac Operator lacZ lacY lacA RNA polymerase Transcription proceeds Repressor (b) Inducer 2012 Pearson Education,Inc. (b)An inducer binds to the repressor and inactivates it so that it no longer can bind to the operator. Transcription by RNA polymerase occurs.诱导物的作用 In lac operon the repressor would be the lac repressor, and the inducer would be allolactose异乳糖
(b) An inducer binds to the repressor and inactivates it so that it no longer can bind to the operator. Transcription by RNA polymerase occurs. 诱导物的作用 In lac operon the repressor would be the lac repressor, and the inducer would be allolactose异乳糖. FLASH 1: lac operon