Linked Life Data

1911945

Source:http://linkedlifedata.com/resource/pubmed/id/1911945

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1991-10-31
pubmed:abstractText
To analyze the DNA binding domain of E coli LexA repressor and to test whether the repressor binds as a dimer to DNA, negative dominant lexA mutations affecting the binding domain have been isolated. A large number of amino acid substitutions between amino acid positions 39 and 46 were introduced using cassette mutagenesis. Mutants defective in DNA binding were identified and then examined for dominance to lexA+. A number of substitutions weakened repressor function partially, whereas other substitutions led to a repressor with no demonstrable activity and a defective dominant phenotype. Since the LexA binding site has dyad symmetry, we infer that this dominance results from interaction of monomers of wild-type LexA protein with mutant monomers and that an oligomeric form of repressor binds to operator. The binding of LexA protein to operator DNA was investigated further using a mutant protein, LexA408, which recognizes a symmetrically altered operator mutant but not wild-type operator. A mixture of mutant LexA408 and LexA+ proteins, but neither individual protein, bound to a hybrid recA operator consisting of mutant and wild-type operator half sites. These results suggest that at least 1 LexA protein monomer interacts with each operator half site. We discuss the role of LexA oligomer formation in binding of LexA to operator DNA.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0300-9084
pubmed:author
pubmed:issnType
Print
pubmed:volume
73
pubmed:geneSymbol
recA
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
449-56
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Repression of the E coli recA gene requires at least two LexA protein monomers.
pubmed:affiliation
Department of Molecular and Cellular Biology, University of Arizona, Tucson 85721.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.