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Structural basis of ? appropriation.

ABSTRACT: Bacteriophage T4 middle promoters are activated through a process called ? appropriation, which requires the concerted effort of two T4-encoded transcription factors: AsiA and MotA. Despite extensive biochemical and genetic analyses, puzzle remains, in part, because of a lack of precise structural information for ? appropriation complex. Here, we report a single-particle cryo-electron microscopy (cryo-EM) structure of an intact ? appropriation complex, comprising AsiA, MotA, Escherichia coli RNA polymerase (RNAP), ?70 and a T4 middle promoter. As expected, AsiA binds to and remodels ? region 4 to prevent its contact with host promoters. Unexpectedly, AsiA undergoes a large conformational change, takes over the job of ? region 4 and provides an anchor point for the upstream double-stranded DNA. Because ? region 4 is conserved among bacteria, other transcription factors may use the same strategy to alter the landscape of transcription immediately. Together, the structure provides a foundation for understanding ? appropriation and transcription activation.

SUBMITTER: Shi J

PROVIDER: S-EPMC6755090 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

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Structural basis of σ appropriation.

Shi Jing J Wen Aijia A Zhao Minxing M You Linlin L Zhang Yu Y Feng Yu Y

Nucleic acids research 20190901 17

Bacteriophage T4 middle promoters are activated through a process called σ appropriation, which requires the concerted effort of two T4-encoded transcription factors: AsiA and MotA. Despite extensive biochemical and genetic analyses, puzzle remains, in part, because of a lack of precise structural information for σ appropriation complex. Here, we report a single-particle cryo-electron microscopy (cryo-EM) structure of an intact σ appropriation complex, comprising AsiA, MotA, Escherichia coli RNA ...[more]

PMID: 31392983

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