1H3L

N-terminal fragment of SigR from Streptomyces coelicolor


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.375 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.258 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Identification and Structure of the Anti-Sigma Factor-Binding Domain of the Disulfide-Stress Regulated Sigma Factor Sigma(R) from Streptomyces Coelicolor

Li, W.Stevenson, C.E.M.Burton, N.Jakimowicz, P.Paget, M.S.B.Buttner, M.J.Lawson, D.M.Kleanthous, C.

(2002) J.Mol.Biol. 323: 225


  • 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. Normall ...

    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.


    Organizational Affiliation

    School of Biological Sciences, University of East Anglia, NR4 7TJ, Norwich, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
RNA POLYMERASE SIGMA FACTOR
A, B
87Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145)Gene Names: sigR
Find proteins for Q7AKG9 (Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145))
Go to UniProtKB:  Q7AKG9
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.375 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.258 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 71.546α = 90.00
b = 71.546β = 90.00
c = 102.794γ = 120.00
Software Package:
Software NamePurpose
DENZOdata reduction
SOLVEphasing
SCALEPACKdata scaling
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-10-03
    Type: Initial release
  • Version 1.1: 2015-09-23
    Type: Source and taxonomy, Version format compliance