Linked Life Data

11676534

Source:http://linkedlifedata.com/resource/pubmed/id/11676534

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2001-10-25
pubmed:abstractText
The Rhodobacter sphaeroides extra cytoplasmic function sigma factor, sigma(E), directs transcription of promoters for the cycA gene (cycA P3) and the rpoEchrR operon (rpoE P1). These genes encode the periplasmic electron carrier cytochrome c(2) and sigma(E)/ChrR, respectively. Using in vitro transcription assays with purified R. sphaeroides core RNA polymerase and sigma(E), we show that ChrR is sufficient to inhibit sigma(E)-dependent transcription. Inhibition is proposed to proceed through a binding interaction, since sigma(E) and ChrR form a 1:1 complex that can be purified when expressed at high levels in Escherichia coli. Active preparations of ChrR and the sigma(E)/ChrR complex each contain stoichiometric zinc. Removal of zinc from ChrR or a single amino acid substitution that abolishes zinc binding, results in a protein that is incapable of inhibiting sigma(E) activity or forming a complex with the sigma factor, indicating that metal binding is important to ChrR activity. Treatment of ChrR with the thiol-modifying reagent p-hydroxymecuriphenylsulfonic acid results in the release of about one mole of zinc per mole of protein. Furthermore, two N-terminal cysteine residues are protected from reaction with the thiol-specific reagent dithionitrobenzoic acid until zinc is removed, suggesting that these residues may be involved in zinc binding. These data indicate that ChrR is a specific anti-sigma factor of sigma(E) that requires zinc for function. Based on amino acid sequence similarity, we propose that ChrR is part of a family of similar anti-sigma factors that are found in alpha and gamma proteobacteria.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-2836
pubmed:author
pubmed:copyrightInfo
Copyright 2001 Academic Press.
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
313
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
485-99
pubmed:dateRevised
2010-8-27
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
The importance of zinc-binding to the function of Rhodobacter sphaeroides ChrR as an anti-sigma factor.
pubmed:affiliation
Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.