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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
3
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pubmed:dateCreated |
1994-1-12
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pubmed:abstractText |
The 434 repressor binds more tightly to OR1 than it does to OR3. The repressor makes several specific contacts with the symmetrically arrayed outer four base-pairs of the 14 base-pair site, and no specific contacts to the central six base-pairs. The sequence of the outer base-pairs of OR1 and OR3 differs only by an A-->G substitution at position 4 in one half-site of OR3, while that of central bases is very different. As expected from sequence analysis of wild-type operators, the data show repressor prefers an A.T base-pair at position 4. The magnitude of this preference depends on operator sequence context and solution conditions. Position 4 changes in the context of OR1 have a greater effect on operator affinity for 434 repressor than do similar changes in OR3. Although OR1 and OR3 display different affinities for 434 repressor, their repressor-operator complexes are similarly insensitive to changes in salt concentration and temperature. By contrast, complexes formed between repressor and position 4 mutant OR1, bearing an A.T-->G.C change, and OR3, which bears a G.C-->A.T change, are affected greatly, and to similar extents, by changes in ionic strength and temperature. Nuclease protection experiments show that 434 repressor protects the DNA phosphate backbone of wild-type operators from cleavage more efficiently than those of mutant operators. These data show that the biochemical and structural properties of a repressor-operator complex, while affected by position 4 base sequence, are independent of the identity of this base. The ability of repressor to recognize the base at position 4 depends on the sequence context at operator positions 5 to 7. Apparently there is an interplay between the bases at operator positions 4 to 7 which has a global effect on the structure of the repressor-operator complex.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Dec
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pubmed:issn |
0022-2836
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
5
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pubmed:volume |
234
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
542-53
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:8254659-Base Composition,
pubmed-meshheading:8254659-Base Sequence,
pubmed-meshheading:8254659-Calorimetry,
pubmed-meshheading:8254659-Coliphages,
pubmed-meshheading:8254659-DNA, Bacterial,
pubmed-meshheading:8254659-DNA, Viral,
pubmed-meshheading:8254659-Escherichia coli,
pubmed-meshheading:8254659-Molecular Sequence Data,
pubmed-meshheading:8254659-Osmolar Concentration,
pubmed-meshheading:8254659-Repressor Proteins,
pubmed-meshheading:8254659-Restriction Mapping,
pubmed-meshheading:8254659-Structure-Activity Relationship
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pubmed:year |
1993
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pubmed:articleTitle |
Operator sequence context influences amino acid-base-pair interactions in 434 repressor-operator complexes.
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pubmed:affiliation |
Department of Biological Sciences, State University of New York at Buffalo 14260.
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pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, U.S. Gov't, P.H.S.
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