1tzc
Crystal structure of phosphoglucose/phosphomannose isomerase from Pyrobaculum aerophilum in complex with 5-phosphoarabinonate
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OverviewOverview
The crystal structure of a dual specificity phosphoglucose isomerase, (PGI)/phosphomannose isomerase from Pyrobaculum aerophilum (PaPGI/PMI) has, been determined in native form at 1.16-A resolution and in complex with, the enzyme inhibitor 5-phosphoarabinonate at 1.45-A resolution. The, similarity of its fold, with the inner core structure of PGIs from, eubacterial and eukaryotic sources, confirms this enzyme as a member of, the PGI superfamily. The almost total conservation of amino acids in the, active site, including the glutamate base catalyst, shows that PaPGI/PMI, uses the same catalytic mechanisms for both ring opening and isomerization, for the interconversion of glucose 6-phosphate (Glc-6-P) to fructose, 6-phosphate (Fru-6-P). The lack of structural differences between native, and inhibitor-bound enzymes suggests this activity occurs without any of, the conformational changes that are the hallmark of the well characterized, PGI family. The lack of a suitable second base in the active site of, PaPGI/PMI argues against a PMI mechanism involving a trans-enediol, intermediate. Instead, PMI activity may be the result of additional space, in the active site imparted by a threonine, in place of a glutamine in, other PGI enzymes, which could permit rotation of the C-2-C-3 bond of, mannose 6-phosphate.
About this StructureAbout this Structure
1TZC is a Single protein structure of sequence from Pyrobaculum aerophilum str. im2 with SO4, PA5 and GOL as ligands. Full crystallographic information is available from OCA.
ReferenceReference
A novel phosphoglucose isomerase (PGI)/phosphomannose isomerase from the crenarchaeon Pyrobaculum aerophilum is a member of the PGI superfamily: structural evidence at 1.16-A resolution., Swan MK, Hansen T, Schonheit P, Davies C, J Biol Chem. 2004 Sep 17;279(38):39838-45. Epub 2004 Jul 13. PMID:15252053
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