1H3L

N-terminal fragment of SigR from Streptomyces coelicolor

1H3L の概要

• エントリーDOI: 10.2210/pdb1h3l/pdb
• 分子名称: RNA POLYMERASE SIGMA FACTOR (2 entities in total)
• 機能のキーワード: transcription, dna-binding, transcription regulation
• 由来する生物種: STREPTOMYCES COELICOLOR A3(2)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 20314.53

構造登録者

Li, W.,Stevenson, C.E.M.,Burton, N.,Jakimowicz, P.,Paget, M.S.B.,Buttner, M.J.,Lawson, D.M.,Kleanthous, C. (登録日: 2002-09-10, 公開日: 2002-10-03, 最終更新日: 2024-05-08)

主引用文献

Li, W.,Stevenson, C.E.M.,Burton, N.,Jakimowicz, P.,Paget, M.S.B.,Buttner, M.J.,Lawson, D.M.,Kleanthous, C.
Identification and Structure of the Anti-Sigma Factor-Binding Domain of the Disulfide-Stress Regulated Sigma Factor Sigma(R) from Streptomyces Coelicolor
J.Mol.Biol., 323:225-, 2002

PubMed Abstract: The extracytoplasmic function (ECF) sigma factor sigma(R) is a global regulator of redox homeostasis in the antibiotic-producing bacterium Streptomyces coelicolor, with a similar role in other actinomycetes such as Mycobacterium tuberculosis. Normally maintained in an inactive state by its bound anti-sigma factor RsrA, sigma(R) dissociates in response to intracellular disulphide-stress to direct core RNA polymerase to transcribe genes, such as trxBA and trxC that encode the enzymes of the thioredoxin disulphide reductase pathway, that re-establish redox homeostasis. Little is known about where RsrA binds on sigma(R) or how it suppresses sigma(R)-dependent transcriptional activity. Using a combination of proteolysis, surface-enhanced laser desorption ionisation mass spectrometry and pull-down assays we identify an N-terminal, approximately 10kDa domain (sigma(RN)) that encompasses region 2 of sigma(R) that represents the major RsrA binding site. We show that sigma(RN) inhibits transcription by an unrelated sigma factor and that this inhibition is relieved by RsrA binding, reaffirming that region 2 is involved in binding to core RNA polymerase but also demonstrating that the likely mechanism by which RsrA inhibits sigma(R) activity is by blocking this association. We also report the 2.4A resolution crystal structure of sigma(RN) that reveals extensive structural conservation with the equivalent region of sigma(70) from Escherichia coli as well as with the cyclin-box, a domain-fold found in the eukaryotic proteins TFIIB and cyclin A. sigma(RN) has a propensity to aggregate, due to steric complementarity of oppositely charged surfaces on the domain, but this is inhibited by RsrA, an observation that suggests a possible mode of action for RsrA which we compare to other well-studied sigma factor-anti-sigma factor systems.

PubMed: 12381317
DOI: 10.1016/S0022-2836(02)00948-8

実験手法

X-RAY DIFFRACTION (2.375 Å)