Publication Date:
1994-11-04
Description:
The three-dimensional structure of a ternary complex of the purine repressor, PurR, bound to both its corepressor, hypoxanthine, and the 16-base pair purF operator site has been solved at 2.7 A resolution by x-ray crystallography. The bipartite structure of PurR consists of an amino-terminal DNA-binding domain and a larger carboxyl-terminal corepressor binding and dimerization domain that is similar to that of the bacterial periplasmic binding proteins. The DNA-binding domain contains a helix-turn-helix motif that makes base-specific contacts in the major groove of the DNA. Base contacts are also made by residues of symmetry-related alpha helices, the "hinge" helices, which bind deeply in the minor groove. Critical to hinge helix-minor groove binding is the intercalation of the side chains of Leu54 and its symmetry-related mate, Leu54', into the central CpG-base pair step. These residues thereby act as "leucine levers" to pry open the minor groove and kink the purF operator by 45 degrees.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schumacher, M A -- Choi, K Y -- Zalkin, H -- Brennan, R G -- GM 24658/GM/NIGMS NIH HHS/ -- GM 49244/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Nov 4;266(5186):763-70.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, Oregon Health Sciences University, Portland 97201-3098.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7973627" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Bacterial Proteins/*chemistry/genetics/metabolism
;
Base Sequence
;
Binding Sites
;
Computer Graphics
;
Crystallography, X-Ray
;
DNA/chemistry/*metabolism
;
DNA-Binding Proteins/*chemistry/genetics/metabolism
;
*Escherichia coli Proteins
;
Hydrogen Bonding
;
Hypoxanthine
;
Hypoxanthines/metabolism
;
Lac Repressors
;
Models, Molecular
;
Molecular Sequence Data
;
Nucleic Acid Conformation
;
*Operator Regions, Genetic
;
Protein Conformation
;
Protein Structure, Secondary
;
Repressor Proteins/*chemistry/genetics/metabolism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
