Dataset Information

Mycobacterium tuberculosis RsdA provides a conformational rationale for selective regulation of ?-factor activity by proteolysis.

ABSTRACT: The relative levels of different ? factors dictate the expression profile of a bacterium. Extracytoplasmic function ? factors synchronize the transcriptional profile with environmental conditions. The cellular concentration of free extracytoplasmic function ? factors is regulated by the localization of this protein in a ?/anti-? complex. Anti-? factors are multi-domain proteins with a receptor to sense environmental stimuli and a conserved anti-? domain (ASD) that binds a ? factor. Here we describe the structure of Mycobacterium tuberculosis anti-?(D) (RsdA) in complex with the -35 promoter binding domain of ?(D) (?(D)4). We note distinct conformational features that enable the release of ?(D) by the selective proteolysis of the ASD in RsdA. The structural and biochemical features of the ?(D)/RsdA complex provide a basis to reconcile diverse regulatory mechanisms that govern ?/anti-? interactions despite high overall structural similarity. Multiple regulatory mechanisms embedded in an ASD scaffold thus provide an elegant route to rapidly re-engineer the expression profile of a bacterium in response to an environmental stimulus.

SUBMITTER: Jaiswal RK

PROVIDER: S-EPMC3597663 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Mycobacterium tuberculosis RsdA provides a conformational rationale for selective regulation of σ-factor activity by proteolysis.

Jaiswal Ravi K RK Prabha Tangirala Surya TS Manjeera Gowravaram G Gopal Balasubramanian B

Nucleic acids research 20130111 5

The relative levels of different σ factors dictate the expression profile of a bacterium. Extracytoplasmic function σ factors synchronize the transcriptional profile with environmental conditions. The cellular concentration of free extracytoplasmic function σ factors is regulated by the localization of this protein in a σ/anti-σ complex. Anti-σ factors are multi-domain proteins with a receptor to sense environmental stimuli and a conserved anti-σ domain (ASD) that binds a σ factor. Here we descr ...[more]

PMID: 23314154

Similar Datasets

Project description:To characterize the roles of SigB and SigF in sigma factor regulation in Mycobacterium tuberculosis, we used chemically inducible recombinant strains to conditionally overexpress sigB and sigF. Using whole genomic microarray analysis and quantitative reverse transcription-PCR, we investigated the resulting global transcriptional changes after sigB induction, and we specifically tested the relative expression of other sigma factor genes after knock-in expression of sigB and sigF. Overexpression of sigB resulted in significant upregulation of genes encoding several early culture filtrate antigens (ESAT-6-like proteins), ribosomal proteins, PE-PGRS proteins, the keto-acyl synthase, KasA, and the regulatory proteins WhiB2 and IdeR. Of note, the induction of sigB did not alter the expression of other sigma factor genes, indicating that SigB is likely to serve as an end regulator for at least one branch of the M. tuberculosis sigma factor regulatory cascade. Analysis of the 5'-untranslated region (UTR) of SigB-dependent transcripts revealed a putative consensus sequence of NGTGG-N(14-18)-NNGNNG. This sequence appeared upstream of both sigB (Rv2710) and the gene following it, ideR (Rv2711), and in vitro transcription analysis with recombinant SigB-reconstituted RNA polymerase confirmed SigB-dependent transcription from each of these promoters. Knock-in expression of sigF revealed that only the sigC gene was significantly upregulated 6 and 12 h after sigF induction. The previously identified SigF promoter consensus sequence AGTTTG-N(15)-GGGTTT was identified in the 5' UTR of the sigC gene, and SigF-dependent in vitro transcription of the promoter upstream of sigC was confirmed by using recombinant SigF-reconstituted RNA polymerase. These two knock-in recombinant strains were tested in a macrophage model of infection which showed that overexpression of sigB and sigF resulted in reduced rates of M. tuberculosis intracellular growth. These results define the SigB promoter consensus recognition sequence and members of the SigB regulon. Moreover, the data suggest that, in addition to serving as an end regulator in a sigma factor cascade, SigB may auto-amplify its own expression under certain conditions.

Dataset Information

Mycobacterium tuberculosis RsdA provides a conformational rationale for selective regulation of ?-factor activity by proteolysis.

Publications

Mycobacterium tuberculosis RsdA provides a conformational rationale for selective regulation of σ-factor activity by proteolysis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets