EspR, a key regulator of Mycobacterium tuberculosis virulence, adopts a unique dimeric structure among helix-turn-helix proteins.

ABSTRACT: EspR is a transcriptional regulator that activates the ESX-1 secretion system during Mycobacterium tuberculosis infection and is critical for pathogenesis. It is unique among DNA-binding proteins as it is secreted as part of a feedback regulatory loop that serves to mitigate transcriptional activity. Here we report the crystal structure of a functional EspR dimer at 2.5-Å resolution. The amino-terminal half of EspR is a helix-turn-helix (HTH) DNA-binding domain and the carboxy terminus consists of a dimerization domain with similarity to the SinR:SinI sporulation regulator of Bacillus subtilis. Surprisingly, the HTH domains of EspR are arranged in an unusual conformation in which they are splayed at an oblique angle to each other, suggesting that EspR binds DNA in a profoundly different wa

SUBMITTER: Rosenberg OS 

PROVIDER: S-EPMC3158157 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature