1nsy
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(New page: 200px<br /><applet load="1nsy" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nsy, resolution 2.0Å" /> '''CRYSTAL STRUCTURE OF ...)
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Revision as of 20:24, 20 November 2007
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CRYSTAL STRUCTURE OF NH3-DEPENDENT NAD+ SYNTHETASE FROM BACILLUS SUBTILIS
Overview
NAD+ synthetase catalyzes the last step in the biosynthesis of, nicotinamide adenine dinucleotide. The three-dimensional structure of, NH3-dependent NAD+ synthetase from Bacillus subtilis, in its free form and, in complex with ATP, has been solved by X-ray crystallography (at 2.6 and, 2.0 angstroms resolution, respectively) using a combination of multiple, isomorphous replacement and density modification techniques. The enzyme, consists of a tight homodimer with alpha/beta subunit topology. The, catalytic site is located at the parallel beta-sheet topological switch, point, where one AMP molecule, one pyrophosphate and one Mg2+ ion are, observed. Residue Ser46, part of the neighboring 'P-loop', is hydrogen, bonded to the pyrophosphate group, and may play a role in promoting the, adenylation of deamido-NAD+ during the first step of the catalyzed, reaction. The deamido-NAD+ binding site, located at the subunit interface, is occupied by one ATP molecule, pointing towards the catalytic center. A, conserved structural fingerprint of the catalytic site, comprising Ser46, is very reminiscent of a related protein region observed in, glutamine-dependent GMP synthetase, supporting the hypothesis that NAD+, synthetase belongs to the newly discovered family of 'N-type' ATP, pyrophosphatases.
About this Structure
1NSY is a Single protein structure of sequence from Bacillus subtilis with MG, ATP, AMP and POP as ligands. Active as NAD(+) synthase (glutamine-hydrolyzing), with EC number 6.3.5.1 Full crystallographic information is available from OCA.
Reference
Crystal structure of NH3-dependent NAD+ synthetase from Bacillus subtilis., Rizzi M, Nessi C, Mattevi A, Coda A, Bolognesi M, Galizzi A, EMBO J. 1996 Oct 1;15(19):5125-34. PMID:8895556
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