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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1995-4-10
pubmed:abstractText
In an attempt to understand the role of ATP as a cofactor at the interaction of the RecA protein with DNA, we have studied the orientation geometries of the cofactor analogs adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S) and guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) in RecA-DNA complexes using flow linear dichroism spectroscopy. Both cofactors promote the formation of RecA-DNA complexes of similar structure as judged from similar orientations of DNA bases. The DNA orientation was probed through the dichroism of the long-wavelength absorption of a DNA analog, poly(d epsilon A). In this way differences between the dichroic spectra of the ATP gamma S-RecA-DNA and GTP gamma S-RecA-DNA complexes, observed in the shorter-wavelength region, are related to orientation at variations of the cofactor chromophores. The results show that the guanine plane of GTP gamma S is oriented parallel with the principal axis of the complex in contrast to the more perpendicular orientation of the DNA bases. This observation directly excludes the possibility that the cofactor could be intercalated between the DNA bases. The orientation of the adenine base of ATP gamma S, which may be similar to that of guanine of GTP gamma S albeit not exactly the same, is also inconsistent with intercalation. The possibility that the cofactor bound to the protein could be intercalated in DNA had been speculated from the observation that some DNA intercalators can induce RecA binding to DNA in the absence of cofactor.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0952-3499
pubmed:author
pubmed:issnType
Print
pubmed:volume
7
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
221-6
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
The cofactor ATP in DNA-RecA complexes is not intercalated between DNA bases.
pubmed:affiliation
Groupe d'Etude Mutagénèse et Cancérogénèse, URA 1342 CNRS, Université Paris Sud, Orsay, France.
pubmed:publicationType
Journal Article