Structural and functional studies on RbpA, a RNA polymerase binding protein in streptomyces coelicolor A3 (2)

Tabib-Salazar, Aline (2012) Structural and functional studies on RbpA, a RNA polymerase binding protein in streptomyces coelicolor A3 (2). Doctoral thesis (PhD), University of Sussex.

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Abstract

RbpA is a RNA polymerase-binding protein that was identified in Streptomyces coelicolor. It is found in all Actinobacteria, including the pathogenic agent Mycobacterium tuberculosis. Streptomyces strains that have an rbpA mutation grow at a slower rate than the wild-type and are more sensitive to the RNAP-targeting antibiotic, rifampicin. RbpA binds to and activates σHrdB, the principal sigma factor that directs transcription of most housekeeping genes in S. coelicolor. Using bacterial two-hybrid analysis and in vitro pull down assays, RbpA was shown to interact with region 1.2-2.4 of σHrdB. This region forms part of a major interface with core RNA polymerase and is involved in the recognition of, and binding to, the -10 promoter element. Rv2050, the homologue of RbpA in M. tuberculosis, was also shown to interact with the principal sigma factor of this organism, σA. Structural studies on RbpA and Rv2050 revealed that it is composed of two regions, a structured N-terminal β-fold region and an flexible or unstable C-terminal region, which interacts with sigma. Alanine-scanning site-directed mutagenesis on the C-terminal region of RbpA identified important residues involved in σHrdB interaction as well as residues that might be involved in transcriptional activation.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Life Sciences > Biochemistry
Subjects: Q Science > QD Chemistry > QD0241 Organic chemistry > QD0415 Biochemistry
Depositing User: Library Cataloguing
Date Deposited: 08 Oct 2012 13:35
Last Modified: 04 Sep 2015 15:31
URI: http://sro.sussex.ac.uk/id/eprint/40905

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