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Structural Basis of Transcription Initiation
- Zhang, Yu, Feng, Yu, Chatterjee, Sujoy, Tuske, Steve, Ho, Mary X., Arnold, Eddy, Ebright, Richard H.
- Science 2012 v.338 no.6110 pp. 1076-1080
- DNA, DNA-directed RNA polymerase, RNA, Thermus thermophilus, crystal structure, gene expression regulation, genes, nucleotide sequences, proteins, transcription (genetics)
- To transcribe a gene, RNA polymerase (RNAP) must unwind the promoter DNA to form a “transcription bubble” and the RNAP-promoter open complex (RPo). The activity of RPo is critical for the regulation of gene expression. Zhang et al. (p. 1076, published online 18 October) describe crystal structures of bacterial RPo, together with the transcription initiation factor σ, from Thermus thermophilus , variously in complex with promoter DNA and an RNA primer. RNAP and σ recognize the promoter through sequence-specific contacts with transcription-bubble, nontemplate-strand DNA. Critical interactions occur through the unstacking of DNA bases and their insertion into pockets on the surfaces of the two proteins, allowing direct sensing of the DNA sequence.