Structural properties of Escherichia coli RNA polymerase Subunits.
Structural properties of Escherichia coli RNA polymerase Subunits.
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大肠杆菌 RNA 聚合酶亚基的结构特性。
DOI：
10.1111/j.1432-1033.1976.tb10286.x
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发表时间：
1976
期刊：
影响因子：
--
通讯作者：
A. Malcolm
中科院分区：
文献类型：
--
作者：
P. Lowe;A. Malcolm
1. RNA-聚合酶-DNA复合物的表面具有暴露的多肽环。2.具有不同特异性的蛋白酶（胰蛋白酶、胰凝乳蛋白酶、枯草杆菌蛋白酶和梭菌蛋白酶）优先切割暴露区域。3.裂解的多肽通过从促进无规卷曲构象的溶剂中复性而重新组装成RNA聚合酶。4.分离的β亚基具有约70000分子量的蛋白水解抗性核。这种抗性多肽可以由胰蛋白酶、胰凝乳蛋白酶、枯草杆菌素或梭菌蛋白酶产生。5.分离的α亚基对蛋白水解具有相对抗性。6.虽然β和β '具有相似的分子量，但在游离溶液中似乎具有不相关的一级序列和明显不同的构象。7.β亚基的消化可被α 2 β亚组装体的形成阻断。8.证据表明，β '在完整的酶（α 2 β β'）具有暴露的多肽环。
1. The surface of the RNA-polymerase-DNA complex possesses an exposed polypeptide loop. 2. Proteinases with differing specificities (trypsin, chymotrypsin, subtilisin and clostripain) preferentially cleave the exposed region. 3. The cleaved polypeptide is reassembled into RNA polymerase by renaturation from a solvent which promotes a random coil conformation. 4. Isolated beta subunit has a proteolytically resistant nucleus of approximately 70000 molecular weight. This resistant polypeptide may be generated by trypsin, chymotrypsin, subiilisin or clostripain. 5. Isolated alpha subunits are comparatively resistant to proteolysis. 6. Although of similar molecular weights beta and beta' appear to have unrelated primary sequences and markedly different conformations in free solution. 7. Digestion of the beta subunit may be blocked by formation of the alpha2beta subassembly. 8. Evidence is presented suggesting that beta' in the intact enzyme (alpha2beta beta') possesses the exposed polypeptide loop.