2R63
STRUCTURAL ROLE OF A BURIED SALT BRIDGE IN THE 434 REPRESSOR DNA-BINDING DOMAIN, NMR, 20 STRUCTURES
Summary for 2R63
| Entry DOI | 10.2210/pdb2r63/pdb |
| Descriptor | REPRESSOR PROTEIN FROM BACTERIOPHAGE 434 (1 entity in total) |
| Functional Keywords | gene regulating protein, phage 434 repressor, helix-turn-helix, dna-binding domain |
| Biological source | Phage 434 |
| Total number of polymer chains | 1 |
| Total formula weight | 6874.87 |
| Authors | Pervushin, K.V.,Billeter, M.,Siegal, G.,Wuthrich, K. (deposition date: 1996-11-13, release date: 1997-06-16, Last modification date: 2024-05-22) |
| Primary citation | Pervushin, K.,Billeter, M.,Siegal, G.,Wuthrich, K. Structural role of a buried salt bridge in the 434 repressor DNA-binding domain. J.Mol.Biol., 264:1002-1012, 1996 Cited by PubMed Abstract: The independently folding 63-residue N-terminal DNA-binding domain of the 434 repressor, 434(1-63), contains a buried Arg10-Glu35 salt bridge. A corresponding salt bridge is found in a variety of prokaryotic and eukaryotic DNA-binding proteins with helix-turn-helix motifs. Here, the NMR solution structures of 434(1-63) and the mutant protein 434[R10M](1-63) were determined to investigate the structural role of this salt bridge. Both proteins contain the same type of global fold, with five alpha-helices and a helix-turn-helix motif formed by the helices II and III. The primary structural difference caused by the Arg10 --> Met mutation is a translation of helix I along its axis relative to the helix II-turn-helix III motif. This limited conformational change is paralleled by a 9 kJ M(-1) decrease of the stability of the folded mutant protein in aqueous solution at pH 4.8. It affects the pKa value of Glu19 as well as the population of a hydrogen bond between the backbone amide proton of Asn16 and the side-chain carboxylate group of Glu19. Using the crystal structure of the 434 repressor dimer complexed with the operator DNA as a basis, model building of the DNA complex with the NMR structure of 434[R10M](1-63) shows that Asn16, which is located on the protein surface, makes direct contact with the DNA and indicates that the point mutation Arg10 --> Met should also lead to modifications of the protein-protein contacts in the complex. PubMed: 9000626DOI: 10.1006/jmbi.1996.0692 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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