Structural insights into the mycobacteria transcription initiation complex from analysis of X-ray crystal structures.

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 ?-subunit C-terminal domain (?CTD) with DNA, and we provide evidence that the ?CTD may play a role in Mtb transcription regulation. Our results reveal the structure of an Actinobacteria-unique insert of the RNAP ?' subunit. Finally, our analysis reveals the disposition of the N-terminal segment of Msm ?A, 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.

SUBMITTER: Hubin EA 

PROVIDER: S-EPMC5511352 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature