A Novel Bacteriophage-encoded RNA Polymerase Binding Protein Inhibits Transcription Initiation and Abolishes Transcription Termination by Host RNA Polymerase
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- 作者：Nechaev ; Sergei ; Yuzenkova ; Yulia ; Niedziela-Majka ; Anita ; Heyduk ; Tomasz ; Severinov ; Konstantin
- 关键词：RNA polymerase ; transcription initiation ; transcription antitermination ; bacteriophage infection ; Xanthomonas oryzae ; RNAP ; RNA polymerase ; LRET ; luminescence resonance energy transfer
- 刊名：Journal of Molecular Biology
- 出版年：2002
- 出版时间：June 28, 2002
- 年：2002
- 卷：320
- 期：1
- 页码：11-22
- 全文大小：409 K
文摘
Xp10 is a lytic bacteriophage of Xanthomonas oryzae, a Gram-negative bacterium that causes rice blight. We purified an Xp10 protein, p7, that binds to and inhibits X.oryzae RNA polymerase (RNAP). P7 is a novel 73 amino acid-long protein; it does not bind to and hence does not affect transcription by Escherichia coli RNAP. Analysis of E.coli/X.oryzae RNAP hybrids locates the p7 binding site to the largest X.oryzae RNAP subunit, β′. Binding of p7 to X.oryzae RNAP holoenzyme prevents large conformational change that places the σ subunit region 4 into the correct position for interaction with the −35 promoter element. As a result, open promoter complex formation on the −10/−35 class promoters is inhibited. Inhibition of promoter complex formation on the extended −10 class promoters is less efficient. The p7 protein also abolishes factor-independent transcription termination by X.oryzae RNAP by preventing the release of nascent RNA at terminators. Further physiological and mechanistic studies of this novel transcription factor should provide additional insights into its biological role and the processes of promoter recognition and transcription termination.