| Autor: |
Zhao N; Department of Biochemistry and Anaerobic Microbiology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0308., Oh W, Trybul D, Thrasher KS, Kingsbury TJ, Larson TJ |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of bacteriology [J Bacteriol] 1994 Apr; Vol. 176 (8), pp. 2393-7. |
| DOI: |
10.1128/jb.176.8.2393-2397.1994 |
| Abstrakt: |
The glp operons of Escherichia coli are negatively controlled by the glp repressor. Comparison of the repressor-binding affinities for consensus and altered consensus operators in vivo showed that all base substitutions at positions 3, 4, 5, and 8 from the center of the palindromic operator caused a striking decrease in repressor binding. Substitutions at other positions had a severe to no effect on repressor binding, depending on the base substitution. The results obtained indicate that the repressor binds with highest affinity to operators with the half-site WATKYTCGWW, where W is A or T, K is G or T, and Y is C or T. Strong cooperative binding of the repressor to tandem operators was demonstrated in vivo. Cooperativity was maximal when two 20-bp operators were directly repeated or when 2 bp separated the two operators. Cooperativity decreased with the deletion of 2 bp or the addition of 4 bp between the individual operators. Cooperativity was eliminated with a 6-bp insertion between the operators. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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