Linked Life Data

11237593

Source:http://linkedlifedata.com/resource/pubmed/id/11237593

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2001-3-12
pubmed:abstractText
We investigated the structure of the active RecA-DNA complex by analyzing the environment of tyrosine residue 65, which is on the DNA-binding surface of the protein. We prepared a modified RecA protein in which the tyrosine residue was replaced by tryptophan, a natural fluorescent reporter, and measured the change in its fluorescence upon binding of DNA and cofactor. The fluorescence of the inserted tryptophan 65 (Trp65) was centered at 345 nm, indicating a partly exposed residue. Binding cofactor, adenosine 5'-O-3-thiotriphosphate (ATPgammaS), alone at a low salt concentration did not change the fluorescence of Trp65, confirming that the residue is not close to the nucleotide. In contrast, the binding of single-stranded DNA quenched the fluorescence of Trp65 in both the presence and absence of ATPgammaS. Trp65 fluorescence was also quenched upon binding a second DNA strand. The fluorescence change depended upon the presence and absence of ATPgammaS, reflecting the difference in the DNA binding. These results indicate that residue 65 is close to both the first and second DNA strands. The degree of quenching depended upon the base composition of DNA, suggesting that the residue 65 interacts with the DNA bases. Binding of DNA with ATPgammaS as well as binding of ATPgammaS alone at high salt concentration shifted the fluorescence emission peak from 345 to 330 nm, indicating a change from a polar to a non-polar environment. Therefore, the environment change around residue 65 would also be linked to a change in conformation and thus the activation of the protein.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
16
pubmed:volume
306
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
189-99
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Interaction of tyrosine 65 of RecA protein with the first and second DNA strands.
pubmed:affiliation
Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Yamadaoka 3-1 Suita 565-0871, Osaka, Japan. kmorimatsu@ucdavis.edu
pubmed:publicationType
Journal Article