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Structural basis for transcription initiation by bacterial ECF ? factors.

ABSTRACT: Bacterial RNA polymerase employs extra-cytoplasmic function (ECF) ? factors to regulate context-specific gene expression programs. Despite being the most abundant and divergent ? factor class, the structural basis of ECF ? factor-mediated transcription initiation remains unknown. Here, we determine a crystal structure of Mycobacterium tuberculosis (Mtb) RNAP holoenzyme comprising an RNAP core enzyme and the ECF ? factor ?H (?H-RNAP) at 2.7?Å, and solve another crystal structure of a transcription initiation complex of Mtb ?H-RNAP (?H-RPo) comprising promoter DNA and an RNA primer at 2.8?Å. The two structures together reveal the interactions between ?H and RNAP that are essential for ?H-RNAP holoenzyme assembly as well as the interactions between ?H-RNAP and promoter DNA responsible for stringent promoter recognition and for promoter unwinding. Our study establishes that ECF ? factors and primary ? factors employ distinct mechanisms for promoter recognition and for promoter unwinding.

SUBMITTER: Li L

PROVIDER: S-EPMC6411747 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Structural basis for transcription initiation by bacterial ECF σ factors.

Li Lingting L Fang Chengli C Zhuang Ningning N Wang Tiantian T Zhang Yu Y

Nature communications 20190311 1

Bacterial RNA polymerase employs extra-cytoplasmic function (ECF) σ factors to regulate context-specific gene expression programs. Despite being the most abundant and divergent σ factor class, the structural basis of ECF σ factor-mediated transcription initiation remains unknown. Here, we determine a crystal structure of Mycobacterium tuberculosis (Mtb) RNAP holoenzyme comprising an RNAP core enzyme and the ECF σ factor σ<sup>H</sup> (σ<sup>H</sup>-RNAP) at 2.7 Å, and solve another crystal struc ...[more]

PMID: 30858373

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