Linked Life Data

17475619

Source:http://linkedlifedata.com/resource/pubmed/id/17475619

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
27
pubmed:dateCreated
2007-7-2
pubmed:abstractText
Conjugative transfer of Agrobacterium Ti plasmids is regulated by TraR, a quorum-sensing activator. Quorum dependence requires TraM, which binds to and inactivates TraR. In this study, we showed that TraR and TraM form a 151-kDa stable complex composed of two TraR and two TraM dimers both in vitro and in vivo. When interacted with TraR bound to tra box DNA, wild-type TraM formed a nucleoprotein complex of 77 kDa composed of one dimer of each protein and DNA. The complex converted to the 151-kDa species with concomitant release of DNA with a half-life of 1.6 h. TraR in the complex still retained tightly bound autoinducer. From these results, we conclude that TraM interacts in a two-step process with DNA-TraR to form a large, stable antiactivation complex. Mutagenesis identified residues of TraR important for interacting with TraM. These residues form two patches, possibly defining the binding interfaces. Consistent with this interpretation, comparison of the trypsin-digested polypeptides of TraR and of TraM with that of the TraR-TraM complex revealed that a tryptic site at position 177 of TraR around these patches is accessible on free TraR but is blocked by TraM in the complex. From these genetic and structural considerations, we constructed three-dimensional models of the complex that shed light on the mechanism of TraM-mediated inhibition of TraR and on TraM-mediated destabilization of the TraR-DNA complex.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
6
pubmed:volume
282
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
19979-91
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Molecular basis of transcriptional antiactivation. TraM disrupts the TraR-DNA complex through stepwise interactions.
pubmed:affiliation
Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, N.I.H., Extramural