2PUD

CRYSTAL STRUCTURE OF THE LACI FAMILY MEMBER, PURR, BOUND TO DNA: MINOR GROOVE BINDING BY ALPHA HELICES

Summary for 2PUD

• Entry DOI: 10.2210/pdb2pud/pdb
• Descriptor: DNA (5'-D(*TP*AP*CP*GP*CP*AP*AP*AP*CP*GP*TP*TP*TP*GP*CP*GP*T )-3'), PROTEIN (PURINE REPRESSOR), HYPOXANTHINE, ... (4 entities in total)
• Functional Keywords: complex (dna-binding protein-dna), dna-binding regulatory protein, transcription-dna complex, transcription/dna
• Biological source: Escherichia coli
• Total number of polymer chains: 2
• Total formula weight: 43343.97

Authors

Schumacher, M.A.,Choi, K.Y.,Zalkin, H.,Brennan, R.G. (deposition date: 1997-10-04, release date: 1998-05-06, Last modification date: 2024-02-21)

Primary citation

Schumacher, M.A.,Choi, K.Y.,Zalkin, H.,Brennan, R.G.
Crystal structure of LacI member, PurR, bound to DNA: minor groove binding by alpha helices.
Science, 266:763-770, 1994

PubMed Abstract: 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.

PubMed: 7973627

Experimental method

X-RAY DIFFRACTION (2.6 Å)