1pgp: Difference between revisions
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'''CRYSTALLOGRAPHIC STUDY OF COENZYME, COENZYME ANALOGUE AND SUBSTRATE BINDING IN 6-PHOSPHOGLUCONATE DEHYDROGENASE: IMPLICATIONS FOR NADP SPECIFICITY AND THE ENZYME MECHANISM''' | '''CRYSTALLOGRAPHIC STUDY OF COENZYME, COENZYME ANALOGUE AND SUBSTRATE BINDING IN 6-PHOSPHOGLUCONATE DEHYDROGENASE: IMPLICATIONS FOR NADP SPECIFICITY AND THE ENZYME MECHANISM''' | ||
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Crystallographic study of coenzyme, coenzyme analogue and substrate binding in 6-phosphogluconate dehydrogenase: implications for NADP specificity and the enzyme mechanism., Adams MJ, Ellis GH, Gover S, Naylor CE, Phillips C, Structure. 1994 Jul 15;2(7):651-68. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/7922042 7922042] | Crystallographic study of coenzyme, coenzyme analogue and substrate binding in 6-phosphogluconate dehydrogenase: implications for NADP specificity and the enzyme mechanism., Adams MJ, Ellis GH, Gover S, Naylor CE, Phillips C, Structure. 1994 Jul 15;2(7):651-68. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/7922042 7922042] | ||
[[Category: Ovis aries]] | [[Category: Ovis aries]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Adams, M J.]] | [[Category: Adams, M J.]] | ||
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[[Category: Naylor, C E.]] | [[Category: Naylor, C E.]] | ||
[[Category: Phillips, C.]] | [[Category: Phillips, C.]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 05:04:03 2008'' | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | |||
Revision as of 05:04, 3 May 2008
CRYSTALLOGRAPHIC STUDY OF COENZYME, COENZYME ANALOGUE AND SUBSTRATE BINDING IN 6-PHOSPHOGLUCONATE DEHYDROGENASE: IMPLICATIONS FOR NADP SPECIFICITY AND THE ENZYME MECHANISM
OverviewOverview
BACKGROUND: The nicotinamide adenine dinucleotide phosphate (NADP)-dependent oxidative decarboxylase, 6-phosphogluconate dehydrogenase, is a major source of reduced coenzyme for synthesis. Enzymes later in the pentose phosphate pathway convert the reaction product, ribulose 5-phosphate, to ribose 5-phosphate. Crystallographic study of complexes with coenzyme and substrate explain the NADP dependence which determines the enzyme's metabolic role and support the proposed general base-general acid mechanism. RESULTS: The refined structures of binary coenzyme/analogue complexes show that Arg33 is ordered by binding the 2'-phosphate, and provides one face of the adenine site. The nicotinamide, while less tightly bound, is more extended when reduced than when oxidized. All substrate binding residues are conserved; the 3-hydroxyl of 6-phosphogluconate is hydrogen bonded to N zeta of Lys183 and the 3-hydrogen points towards the oxidized nicotinamide. The 6-phosphate replaces a tightly bound sulphate in the apo-enzyme. CONCLUSIONS: NADP specificity is achieved primarily by Arg33 which binds the 2'-phosphate but, in its absence, obscures the adenine pocket. The bound oxidized nicotinamide is syn; hydride transfer from bound substrate to the nicotinamide si- face is achieved with a small movement of the nicotinamide nucleotide. Lys183 may act as general base. A water bound to Gly130 in the coenzyme domain is the most likely acid required in decarboxylation. The dihydronicotinamide ring of NADPH competes for ligands with the 1-carboxyl of 6-phosphogluconate.
About this StructureAbout this Structure
1PGP is a Single protein structure of sequence from Ovis aries. Full crystallographic information is available from OCA.
ReferenceReference
Crystallographic study of coenzyme, coenzyme analogue and substrate binding in 6-phosphogluconate dehydrogenase: implications for NADP specificity and the enzyme mechanism., Adams MJ, Ellis GH, Gover S, Naylor CE, Phillips C, Structure. 1994 Jul 15;2(7):651-68. PMID:7922042 Page seeded by OCA on Sat May 3 05:04:03 2008