Structural insights into the mycobacteria transcription initiation complex from analysis of X-ray crystal structures.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28703128.
- Also identified by DOI 10.1038/ncomms16072 and PMC identifier 5511352.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The mycobacteria RNA polymerase (RNAP) is a target for antimicrobials against tuberculosis, motivating structure/function studies. Here we report a 3.2 Å-resolution crystal structure of a Mycobacterium smegmatis (Msm) open promoter complex (RPo), along with structural analysis of the Msm RPo and a previously reported 2.76 Å-resolution crystal structure of an Msm transcription initiation complex with a promoter DNA fragment. We observe the interaction of the Msm RNAP α-subunit C-terminal domain (αCTD) with DNA, and we provide evidence that the αCTD may play a role in Mtb transcription regulation. Our results reveal the structure of an Actinobacteria-unique insert of the RNAP β' subunit. Finally, our analysis reveals the disposition of the N-terminal segment of Msm σ<sup>A</sup>, which may comprise an intrinsically disordered protein domain unique to mycobacteria. The clade-specific features of the mycobacteria RNAP provide clues to the profound instability of mycobacteria RPo compared with E. coli.
Medical subject headings
- DNA-Directed RNA Polymerases
- Multiprotein Complexes
- Mycobacterium smegmatis
- Promoter Regions, Genetic
- Transcription, Genetic