Martin E, Sagitov V, Burova E, Nikiforov V, Goldfarb A
Department of Microbiology, Columbia University College of Physicians and Surgeons, New York, New York 10032.
J Biol Chem. 1992 Oct 5;267(28):20175-80.
Deletion of 10 amino acids from a conserved motif in the beta subunit of Escherichia coli RNA polymerase (RNAP) leads to an interrupted transcription cycle and lethal phenotype. RNAP carrying the mutant subunit retains catalytic function and specificity of promoter recognition but is unable to efficiently hold onto DNA in the binary complex, resulting in a diminished initiation frequency. However, inefficient initiation by the mutant enzyme leads to processive and stable ternary elongating complex. Thus, the mutation dissects the traits of promoter selectivity, binary complex stability, and ternary complex processivity reflecting compartmentalization of function within the RNAP molecule.
从大肠杆菌RNA聚合酶（RNAP）β亚基的一个保守基序中删除10个氨基酸会导致转录周期中断和致死表型。携带突变亚基的RNAP保留了催化功能和启动子识别特异性，但在二元复合物中无法有效地与DNA结合，导致起始频率降低。然而，突变酶的低效起始会导致持续且稳定的三元延伸复合物。因此，该突变剖析了启动子选择性、二元复合物稳定性和三元复合物持续性的特征，反映了RNAP分子内功能的区室化。
