2i3a
From Proteopedia
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'''Crystal structure of N-Acetyl-gamma-Glutamyl-Phosphate Reductase (Rv1652) from Mycobacterium tuberculosis''' | '''Crystal structure of N-Acetyl-gamma-Glutamyl-Phosphate Reductase (Rv1652) from Mycobacterium tuberculosis''' | ||
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[[Category: Moraidin, F.]] | [[Category: Moraidin, F.]] | ||
[[Category: XMTB, Mycobacterium Tuberculosis Structural Proteomics Project.]] | [[Category: XMTB, Mycobacterium Tuberculosis Structural Proteomics Project.]] | ||
| - | [[Category: | + | [[Category: Dimer interface beta sandwich]] |
| - | [[Category: | + | [[Category: Mycobacterium tuberculosis structural proteomics project]] |
| - | [[Category: | + | [[Category: Rossmann fold]] |
| - | [[Category: | + | [[Category: Structural genomic]] |
| - | [[Category: | + | [[Category: Tetramer]] |
| - | [[Category: | + | [[Category: Xmtb]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 07:01:09 2008'' | |
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Revision as of 04:01, 4 May 2008
Crystal structure of N-Acetyl-gamma-Glutamyl-Phosphate Reductase (Rv1652) from Mycobacterium tuberculosis
Overview
The enzyme N-acetyl-gamma-glutamyl-phosphate reductase (AGPR) catalyzes the nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reductive dephosphorylation of N-acetyl-gamma-glutamyl-phosphate to N-acetylglutamate-gamma-semialdehyde. This reaction is part of the arginine biosynthetic pathway that is essential for some microorganisms and plants, in particular, for Mycobacterium tuberculosis (Mtb). The structures of apo MtbAGPR in the space groups P2(1)2(1)2(1) and C2 and the structure of MtbAGPR bound to the cofactor NADP(+) have been solved and analyzed. Each MtbAGPR subunit consists of alpha/beta and alpha+beta domains; NADP(+) is bound in the cleft between them. The hydrogen bonds and hydrophobic contacts between the enzyme and cofactor have been examined. Comparison of the apo and the bound enzyme structures has revealed a conformational change in MtbAGPR upon NADP(+) binding. Namely, a loop (Leu88 to His92) moves more than 5 A to confine sterically the cofactor's adenine moiety in a hydrophobic pocket. To identify the catalytically important residues in MtbAGPR, a docking of the substrate to the enzyme has been performed using the present structure of the MtbAGPR/NADP(+) complex. It reveals that residues His217 and His219 could form hydrogen bonds with the docked substrate. In addition, an ion pair could form between the substrate phosphate group and the guanidinium group of Arg114. These interactions optimally place and orient the substrate for subsequent nucleophilic attack by Cys158 on the substrate gamma-carboxyl group. His219 is the most probable general base to accept a proton from Cys158 and an adjacent ion pair interaction with the side-chain carboxyl group of Glu222 could help to stabilize the resulting positive charge on His219. For this catalytic triad to function efficiently it requires a small conformational change of the order of 1 A in the loop containing His217 and His219; this could easily result from the substrate binding.
About this Structure
2I3A is a Single protein structure of sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA.
Reference
Crystal structure of N-acetyl-gamma-glutamyl-phosphate reductase from Mycobacterium tuberculosis in complex with NADP(+)., Cherney LT, Cherney MM, Garen CR, Niu C, Moradian F, James MN, J Mol Biol. 2007 Apr 13;367(5):1357-69. Epub 2007 Jan 20. PMID:17316682 Page seeded by OCA on Sun May 4 07:01:09 2008
Categories: Mycobacterium tuberculosis | N-acetyl-gamma-glutamyl-phosphate reductase | Single protein | Cherney, L T. | Cherney, M M. | Garen, C R. | James, M N.G. | Moraidin, F. | XMTB, Mycobacterium Tuberculosis Structural Proteomics Project. | Dimer interface beta sandwich | Mycobacterium tuberculosis structural proteomics project | Rossmann fold | Structural genomic | Tetramer | Xmtb
