Linked Life Data

14731277

Source:http://linkedlifedata.com/resource/pubmed/id/14731277

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2004-1-20
pubmed:databankReference
pubmed:abstractText
TraR is a quorum-sensing transcription factor from Agrobacterium tumefaciens that regulates replication and conjugation genes of the tumour-inducing (Ti) plasmid. TraR activity requires the autoinducer pheromone N-3-oxooctanoyl-l-homoserine lactone (OOHL). Structural studies of TraR-OOHL-DNA complexes showed that one molecule of OOHL is completely engulfed within the N-terminal domain of each TraR subunit. TraR is thought to bind OOHL via four hydrogen bonds, three of them direct and one water mediated, and by numerous hydrophobic interactions. Here, we show that all residues predicted to hydrogen bond with OOHL are essential for wild-type protein function. Mutants that failed to detect OOHL in vivo invariably failed to sequester exogenous OOHL. We showed previously that TraR is protected from cellular proteases by OOHL, and now show that mutants that failed to detect OOHL were also not protected from proteolysis by OOHL. We also describe several mutants with altered autoinducer specificity. Three mutants (T129V, T129A and T115I) detected 3-oxo-AHLs and 3-unsubstituted AHLs with equal sensitivity, indicating that these mutations perturb the water-mediated hydrogen bond to the 3-oxo moiety of OOHL. Three other mutants (A49I, A49M and Q58L) preferentially detected AHLs containing six or seven carbon atoms rather than eight. The bulkier residues in these mutations appear to have occupied a portion of the OOHL binding site, interfering with binding of the acyl chain of AHLs.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
51
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
765-76
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Site-directed mutagenesis of a LuxR-type quorum-sensing transcription factor: alteration of autoinducer specificity.
pubmed:affiliation
Department of Microbiology, 360 A Wing Hall, Cornell University, Ithaca, New York 14853, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.