Mustaev A, Kashlev M, Lee J Y, Polyakov A, Lebedev A, Zalenskaya K, Grachev M, Goldfarb A, Nikiforov V
Institute of Molecular Genetics, Union of Soviet Socialist Republics Academy of Sciences, Moscow.
J Biol Chem. 1991 Dec 15;266(35):23927-31.
The active center of DNA-dependent RNA polymerase performs the principal biochemical reaction of gene expression. Using cross-linkable substrate analogs and site-directed mutations, two evolutionarily invariant amino acids in the beta subunit of the Escherichia coli enzyme (Lys1065 and His1237) were mapped close to the binding site of the priming substrate of the reaction. Surprisingly, the mutational substitution of these residues (Lys1065----Arg and His1237----Ala) did not inactivate the catalytic function, but inhibited transition from the initiation to the elongation stage of transcription.
依赖DNA的RNA聚合酶的活性中心执行基因表达的主要生化反应。利用可交联的底物类似物和定点突变技术，绘制出大肠杆菌该酶β亚基中两个进化上不变的氨基酸（Lys1065和His1237）靠近该反应引发底物的结合位点。令人惊讶的是，这些残基的突变取代（Lys1065→Arg和His1237→Ala）并没有使催化功能失活，但抑制了转录从起始阶段到延伸阶段的转变。
