T7 RNA聚合酶中协同区域的研究

The studies of cooperative regions in T7 RNA polymerase.

作者信息

Protasevich I I, Memelova L V, Kochetkov S N, Makarov A A

机构信息

Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow.

出版信息

FEBS Lett. 1994 Aug 8;349(3):429-32. doi: 10.1016/0014-5793(94)00718-7.

DOI:10.1016/0014-5793(94)00718-7

PMID:8050609

Abstract

The heat denaturation of bacteriophage T7 RNA polymerase (T7RNAP) was studied by scanning microcalorimetry. The thermodynamic parameters of the denaturation were estimated within the pH range 6-9. The analysis of the denaturation curves showed the presence of two cooperative parts of the T7RNAP molecule melting according to the 'all-or-none' principle. The molecular masses of these parts were determined as 22 and 77 kDa. These values are close to the molecular masses of protein domains obtained from X-ray diffraction and limited trypsinolysis data. The smaller N-terminal domain was shown to increase the thermostability of the 'catalytic' C-terminal domain within the intact T7RNAP molecule.

摘要

通过扫描量热法研究了噬菌体T7 RNA聚合酶（T7RNAP）的热变性。在pH值6 - 9范围内估算了变性的热力学参数。对变性曲线的分析表明，T7RNAP分子的熔化存在两个根据“全或无”原则协同的部分。这些部分的分子量测定为22 kDa和77 kDa。这些值与从X射线衍射和有限胰蛋白酶消化数据获得的蛋白质结构域的分子量相近。结果表明，在完整的T7RNAP分子中，较小的N端结构域可提高“催化”C端结构域的热稳定性。