Autoregulation of a bacterial σ factor explored by using segmental isotopic labeling and NMR

• DOI: 10.1073/pnas.132033899
• Publication Date: 2002-07-28T22:26:28Z
• Authors: Julio A. Camarero; Alexander Shekhtman; Elizabeth A. Camp...; Mark Chlenov; Tanja M. Gruber; Donald A. Bryant; Seth A. Darst; David Cowburn; Tom W. Muir
• Keywords: Sigma factor

Bacterial σ factors combine with the catalytic core RNA polymerase to direct process of transcription initiation through sequence-specific interactions −10 and −35 elements promoter DNA. In absence polymerase, DNA-binding function is autoinhibited by its own N-terminal 90 amino acids (region 1.1), putatively a interaction conserved region 4.2, which binds element. present work, this mechanism autoinhibition was studied using combination NMR spectroscopy segmental isotopic labeling 70 -like subunit from Thermotoga maritima . Our data argue strongly against high-affinity between these two domains. Instead we suggest that DNA binding occurs an indirect steric and/or electrostatic mechanism. More generally, work illustrates power for probing molecular in large proteins NMR.