STRUCTURAL STUDIES OF RNA POLYMERASE COMPLEXES

RNA聚合酶是细菌基因表达和调控的中心酶。最近，该实验室已经解决了核心RNAP（酶的过程形式）的x射线晶体结构，为该酶与其他亚基和配体相互作用的后续结构研究开辟了道路。本提案的总体目标是了解与酶结构相关的转录机制。对全酶结构的揭示将有助于深入了解sigma因子如何使RNAP获得启动子特异性、启动转录和调节酶的基因抑制剂，并将增加我们目前对转录机制的理解。这些结构也与针对细菌病原体的抗生素设计的医学研究极为相关。这一建议将通过核心RNAP的x射线晶体学与以下因素的复合来完成：1)内务sigma因子（SigA）；2)起始核苷酸三磷酸（ATP）；3)二核苷酸（ApU）和4)抗生素利福平和溶链霉素。

RNA polymerase is the central enzyme of gene expression and regulation in bacteria. Recently this laboratory has solved the X-ray crystal structure of core RNAP (the processive form of the enzyme) opening a path for subsequent structural studies of this enzyme's interaction with additional subunits and ligands. The overall goal of this proposal is to understand the mechanism of transcription in relation to the structure of the enzyme. Revelation of the holoenzyme structure would add great insight to how the sigma factor allows RNAP to acquire promoter specificity, initiate transcription and regulate gene inhibitors of the enzyme, will increase our current understanding of the transcription mechanisms. These structures are also extremely relevant to medical research for anti-biotic design against bacterial pathogens. This proposal will be accomplished by X-ray crystallography of core RNAP complexed with the following factors: 1) the housekeeping sigma factor (SigA); 2) an initiating nucleotide tri- phosphate, (ATP); 3) a dinucleotide (ApU) and 4) the antibiotics rifampican and streptolydigin.