1ntc
SOLUTION STRUCTURE OF THE DNA-BINDING DOMAIN OF NTRC WITH THREE ALANINE SUBSTITUTIONS
Structural highlights
FunctionNTRC_SALTY Member of the two-component regulatory system NtrB/NtrC involved in the activation of nitrogen assimilatory genes such as GlnA. NtrC is phosphorylated by NtrB and interacts with sigma-54. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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