[理學(xué)]第6章原核基因表達調(diào)控-展示頁
2024-12-17 01:05本頁面
【正文】 tion)： 通過小分子誘導(dǎo)物參與 , 使阻抑物失活或活化激活劑來實現(xiàn)對基因或操縱子表達的調(diào)控 。 誘導(dǎo)與阻遏 1. 2 表達調(diào)控水平 轉(zhuǎn)錄水平 (1) DNA的結(jié)構(gòu) (2) RNA聚合酶的功能 (3) 蛋白因子及其他小分子配基的相互作用 轉(zhuǎn)錄后水平 (1) 翻譯的起始、延伸及終止 (2) 蛋白質(zhì)產(chǎn)物的加工、修飾、折疊及轉(zhuǎn)運 調(diào)控類型與特點 負(fù)控誘導(dǎo)系統(tǒng) 正控誘導(dǎo)系統(tǒng) 負(fù)控阻遏系統(tǒng) 正控阻遏系統(tǒng) 調(diào)控類型與特點 2 乳糖操縱子 乳糖操縱子的結(jié)構(gòu)組成 乳糖操縱子的調(diào)控模型 乳糖操縱子的結(jié)構(gòu)組成 The lac operon includes cisactihng regulator elements and proteincoding structural genes 乳糖操縱子的調(diào)控模型 乳糖操縱子的負(fù)調(diào)控 乳糖操縱子的正調(diào)控 (1) 負(fù)調(diào)控位點 操縱基因 ① 位置 。 ② 活性控制 (3) 阻抑物與操縱基因的作用分析 (4) 乳糖操縱子的負(fù)控誘導(dǎo)系統(tǒng) 乳糖操縱子的負(fù)調(diào)控 Repressor and RNA polymerase bind at sites that overlap around the transcription startpoint of the lac operon. 5~+21 Lac 操縱基因的位置 The lac operator has a symmetrical sequence. The sequence is numbered relative to the startpoint for transcription at +1. Lac 操縱基因的序列特征 Lac阻抑物的結(jié)構(gòu)特征 N end C end The repressor tetramer consists of two dimers. Dimers are held together by contacts involving core domain 2 as well as by the oligomerization helix. The dimers are linked into the tetramer by the oligomerization interface. Repressor maintains the lac operon in the inactive condition by binding to the operator. The shape of the repressor is represented as a series of connected domains as revealed by its crystal structure Inducer changes the structure of the core so that the headpieces of a repressor dimer are no longer in an orientation that permits binding to DNA. Lac阻抑物的活性控制 阻抑物與操縱基因的作用分析 Lac repressor binds strongly and specifically to its operator, but is released by inducer. Virtually all the repressor in the cell is bound to DNA. Repression affects the sites at which repres
教學(xué)課件相關(guān)推薦
鄂ICP備17016276號-1