1u0e
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(New page: 200px<br /><applet load="1u0e" size="450" color="white" frame="true" align="right" spinBox="true" caption="1u0e, resolution 1.60Å" /> '''Crystal structure of...)
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Revision as of 01:37, 21 November 2007
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Crystal structure of mouse phosphoglucose isomerase
Overview
Phosphoglucose isomerase (PGI) is an enzyme of glycolysis that, interconverts glucose 6-phosphate (G6P) and fructose 6-phosphate (F6P), but, outside the cell, is a multifunctional cytokine. High-resolution, crystal structures of the enzyme from mouse have been determined in native, form and in complex with the inhibitor erythrose 4-phosphate, and with the, substrate glucose 6-phosphate. In the substrate-bound structure, the, glucose sugar is observed in both straight-chain and ring forms. This, structure supports a specific role for Lys518 in enzyme-catalyzed ring, opening and we present a "push-pull" mechanism in which His388 breaks the, O5-C1 bond by donating a proton to the ring oxygen atom and, simultaneously, Lys518 abstracts a proton from the C1 hydroxyl group. The, reverse occurs in ring closure. The transition from ring form to, straight-chain substrate is achieved through rotation of the C3-C4 bond, which brings the C1-C2 region into close proximity to Glu357, the base, catalyst for the isomerization step. The structure with G6P also explains, the specificity of PGI for glucose 6-phosphate over mannose 6-isomerase, (M6P). To isomerize M6P to F6P requires a rotation of its C2-C3 bond but, in PGI this is sterically blocked by Gln511.
About this Structure
1U0E is a Single protein structure of sequence from Mus musculus with SO4, BME and GOL as ligands. Active as Glucose-6-phosphate isomerase, with EC number 5.3.1.9 Full crystallographic information is available from OCA.
Reference
The crystal structure of mouse phosphoglucose isomerase at 1.6A resolution and its complex with glucose 6-phosphate reveals the catalytic mechanism of sugar ring opening., Graham Solomons JT, Zimmerly EM, Burns S, Krishnamurthy N, Swan MK, Krings S, Muirhead H, Chirgwin J, Davies C, J Mol Biol. 2004 Sep 17;342(3):847-60. PMID:15342241
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