Severinov K, Mustaev A, Severinova E, Kozlov M, Darst S A, Goldfarb A
Public Health Research Institute, New York, New York 10016, USA.
J Biol Chem. 1995 Dec 8;270(49):29428-32. doi: 10.1074/jbc.270.49.29428.
Ribonucleotide analogs bound in the initiating site of Escherichia coli RNA polymerase-promoter complex were cross-linked to the beta subunit. Using limited proteolysis and chemical degradation, the cross-link was mapped to a segment of beta between amino acids Val516 and Arg540. This region (Rif-cluster I) is known to harbor many rifampicin-resistant (RifR) mutations. The results demonstrate that Rif-culster I is part of the "5'-face" of the active center and provide structural basis for the long-known effects of RifR mutations on transcription initiation, elongation, and termination.
与大肠杆菌RNA聚合酶-启动子复合物起始位点结合的核糖核苷酸类似物与β亚基发生了交联。通过有限蛋白酶解和化学降解，将交联定位到β亚基中氨基酸Val516和Arg540之间的一段区域。已知该区域（利福平簇I）含有许多利福平抗性（RifR）突变。结果表明，利福平簇I是活性中心“5'-面”的一部分，并为长期以来已知的RifR突变对转录起始、延伸和终止的影响提供了结构基础。
