4)Transcription elongation:转录的延伸： The process that the RNA polymerase leaves the promoter and moves along the template,making the nascent RNA extension.是指RNA聚合酶离开启动子， 沿DNA链移动并使新生RNA链不断伸长的过程。 2025/5/15 21
2025/5/15 21 4) Transcription elongation: 转录的延伸： The process that the RNA polymerase leaves the promoter and moves along the template, making the nascent RNA extension. 是指RNA聚合酶离开启动子， 沿DNA链移动并使新生RNA链不断伸长的过程
5)Transcription termination:转录的终止： When the nascent rNA reaches to the transcription termination site,no more new phosphodiester bond is formed by RNA polymerase.The RNA-DNA hybrid separates and the transcription bubble collapsed.DNA restored to double-stranded status and both RNA polymerase and nascent RNA are released from the template.当RNA链延伸到转录终 止位点时，RNA聚合酶不再形成新的磷酸二酯键， RNA-DNA杂合物分离，转录泡瓦解，DNA恢复成 双链状态，而RNA聚合酶和RNA链都被从模板上 2释啵出来。 22
2025/5/15 22 5) Transcription termination: 转录的终止： When the nascent RNA reaches to the transcription termination site, no more new phosphodiester bond is formed by RNA polymerase. The RNA-DNA hybrid separates and the transcription bubble collapsed. DNA restored to double-stranded status and both RNA polymerase and nascent RNA are released from the template. 当RNA链延伸到转录终 止位点时，RNA聚合酶不再形成新的磷酸二酯键， RNA-DNA杂合物分离，转录泡瓦解，DNA恢复成 双链状态，而RNA聚合酶和RNA链都被从模板上 释放出来
RNA 6kamto8m nitiation起始 Elongation延伸 Termination终止 2025/5/15 23
2025/5/15 23 Initiation 起始 Elongation 延伸 Termination 终止
五、RNA polymerase RNA聚合酶： RNA polymerase is the key enzyme in transcription.It uses DNA strand as template,the four types of nucleoside triphosphates as substrates,Mg2+/Mn2+as co-factors,to catalyze initiation,elongation and termination of RNA synthesis.It needs no primer,the product is RNA strand that complementary to its DNA template.是转录过程最关键的酶。 以DNA链为模板，以4种核苷三磷酸为活性前体，并以 Mg2+Mn2+为辅助因子，催化RNA链的起始、延伸、终止， 它不需要任何引物，催化生成的产物是与DNA模板链互补的 RNA. 绝大多数RNA聚合酶由多个亚基组成。 2025/5/15 24
2025/5/15 24 五、RNA polymerase RNA聚合酶： RNA polymerase is the key enzyme in transcription. It uses DNA strand as template, the four types of nucleoside triphosphates as substrates, Mg2+/Mn2+ as co-factors, to catalyze initiation, elongation and termination of RNA synthesis. It needs no primer, the product is RNA strand that complementary to its DNA template. 是转录过程最关键的酶。 以DNA链为模板，以4种核苷三磷酸为活性前体，并以 Mg2+/Mn2+为辅助因子，催化RNA链的起始、延伸、终止， 它不需要任何引物，催化生成的产物是与DNA模板链互补的 RNA。 绝大多数RNA聚合酶由多个亚基组成
1.The RNA polymerases in prokaryotes 原 核生物RNA聚合酶： 1)holoen☑yme (全酶)： The protein complex composed of five subunits B'B a@o 由5种亚基组成的蛋白复合物 The molecular weight of the complex is about 450kD,it makes the initiation start at the specific site. 25厨量约为450kD,可以使转录在特定位点开始 25
2025/5/15 25 1. The RNA polymerases in prokaryotes 原 核生物RNA聚合酶： 1) holoenzyme （全酶） ： The protein complex composed of five subunits 由5种亚基组成的蛋白复合物 α β β’ ω σ β’ β α2 ωσ The molecular weight of the complex is about 450kD, it makes the initiation start at the specific site. 分子量约为450kD，可以使转录在特定位点开始