Structural highlights
FunctionPGMI_PYRAE Catalyzes the isomerization of both glucose 6-phosphate and epimeric mannose 6-phosphate at a similar catalytic efficiency. 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 crystal structure of a dual-specificity phosphoglucose/phosphomannose isomerase from the crenarchaeon Pyrobaculum aerophilum (PaPGI/PMI) has been determined in complex with glucose 6-phosphate at 1.16 A resolution and with fructose 6-phosphate at 1.5 A resolution. Subsequent modeling of mannose 6-phosphate (M6P) into the active site of the enzyme shows that the PMI activity of this enzyme may be due to the additional space imparted by a threonine. In PGIs from bacterial and eukaryotic sources, which cannot use M6P as a substrate, the equivalent residue is a glutamine. The increased space may permit rotation of the C2-C3 bond in M6P to facilitate abstraction of a proton from C2 by Glu203 and, after a further C2-C3 rotation of the resulting cis-enediolate, re-donation of a proton to C1 by the same residue. A proline residue (in place of a glycine in PGI) may also promote PMI activity by positioning the C1-O1 region of M6P. Thus, the PMI reaction in PaPGI/PMI probably uses a cis-enediol mechanism of catalysis, and this activity appears to arise from a subtle difference in the architecture of the enzyme, compared to bacterial and eukaryotic PGIs. Structural basis for phosphomannose isomerase activity in phosphoglucose isomerase from Pyrobaculum aerophilum: a subtle difference between distantly related enzymes.,Swan MK, Hansen T, Schonheit P, Davies C Biochemistry. 2004 Nov 9;43(44):14088-95. PMID:15518558[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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