1ntc
From Proteopedia
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SOLUTION STRUCTURE OF THE DNA-BINDING DOMAIN OF NTRC WITH THREE ALANINE SUBSTITUTIONS
Overview
The structure of the 20 kDa C-terminal DNA-binding domain of NtrC from, Salmonella typhimurium (residues Asp380-Glu469) with alanine replacing, Arg456, Asn457, and Arg461, was determined by NMR spectroscopy. NtrC is a, homodimeric enhancer-binding protein that activates the transcription of, genes whose products are required for nitrogen metabolism. The 91-residue, C-terminal domain contains the determinants necessary for dimerization and, DNA-binding of the full length protein. The mutant protein does not bind, to DNA but retains many characteristics of the wild-type protein, and the, mutant domain expresses at high yield (20 mg/l) in minimal medium., Three-dimensional (1)H/(13)C/(15)N triple-resonance, (1)H-(13)C-(13)C-(1)H, correlation and (15)N-separated nuclear Overhauser effect (NOE), spectroscopy experiments were used to make backbone and side-chain, (1)H,(15)N, and (13)C assignments. The structures were calculated using a, total of 1580 intra and inter-monomer distance and hydrogen bond, restraints (88 hydrogen bonds; 44 hydrogen bond restraints), and 88 phi, dihedral restraints for residues Asp400 through Glu469 in both monomers. A, total of 54 ambiguous restraints (intra or inter-monomer) involving, residues close to the 2-fold symmetry axis were also included. Each, monomer consists of four helical segments. Helices A (Trp402-Leu414) and B, (Leu421-His440) join with those of another monomer to form an antiparallel, four-helix bundle. Helices C (Gln446-Leu451) and D (Ala456-Met468) of each, monomer adopt a classic helix-turn-helix DNA-binding fold at either end of, the protein. The backbone rms deviation for the 28 best of 40 starting, structures is 0.6 (+/-0.2) A. Structural differences between the, C-terminal domain of NtrC and the homologous Factor for Inversion, Stimulation are discussed.
About this Structure
1NTC is a Single protein structure of sequence from Salmonella typhimurium. Full crystallographic information is available from OCA.
Reference
Solution structure of the DNA-binding domain of NtrC with three alanine substitutions., Pelton JG, Kustu S, Wemmer DE, J Mol Biol. 1999 Oct 8;292(5):1095-110. PMID:10512705
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