Linked Life Data

8387604

Source:http://linkedlifedata.com/resource/pubmed/id/8387604

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1993-6-4
pubmed:abstractText
RecQ protein of Escherichia coli is a DNA helicase implicated in the RecF pathway of genetic recombination. To gain insight into the mode of its action, the effect of single-stranded DNA-binding proteins (SSBs) on the RecQ-mediated unwinding reaction was investigated. When the unwinding of M13-based, circular partially duplex substrates was measured as a function of the enzyme dose, a markedly sigmoidal relation was revealed, with relatively large amounts of the enzyme being necessary for substantial unwinding to occur. For instance, unwinding 50% of a 71 base-pair (bp) partial duplex substrate in ten minutes required an enzyme-to-substrate molar ratio of about 60. However, these features, indicating the enzyme's "inefficiency", were reversed by SSBs: in the presence of a saturating amount of E. coli SSB the sigmoidal relation was converted to a typically hyperbolic one, and the enzyme-to-substrate molar ratio at 50% unwinding of the 71 bp substrate was reduced to as low as 0.5. Phage T4 gene 32 protein also showed similar stimulatory activity. Further, the single-stranded DNA-dependent ATPase activity of RecQ was found to be relatively insensitive to E. coli SSB; its large excess brought about only a 60% inhibition. It is postulated that RecQ helicase is highly adapted to an SSB-rich environment, where the strand exchange reaction mediated by RecA protein, perhaps coupled closely with the RecQ reaction, should also take place.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
230
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1145-50
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
RecQ DNA helicase of Escherichia coli. Characterization of the helix-unwinding activity with emphasis on the effect of single-stranded DNA-binding protein.
pubmed:affiliation
Department of Microbiology, Faculty of Dentistry, Kyushu University, Fukuoka, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't