1ahp

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spinqualitylabelsall models 1ahp, resolution 3.0Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

OLIGOSACCHARIDE SUBSTRATE BINDING IN ESCHERICHIA COLI MALTODEXTRIN PHSPHORYLASE

Overview

The crystal structure of E. coli maltodextrin phosphorylase, co-crystallized with an oligosaccharide has been solved at 3.0 A, resolution, providing the first structure of an oligosaccharide bound at, the catalytic site of an alpha-glucan phosphorylase. An induced fit, mechanism brings together two domains across the catalytic site tunnel. A, stacking interaction between the glucosyl residue and the aromatic group, of a tyrosine residue at a sub-site remote (8 A) from the catalytic site, provides a key element in substrate recognition; mutation of this residue, to Ala decreases the Kcat/Km by 10(4). Extrapolation of the results to, substrate binding across the site of attack by phosphorolysis indicates a, likely alteration in the glycosidic torsion angles from their preferred, values, an alteration that appears to be important for the catalytic, mechanism.

About this Structure

1AHP is a Single protein structure of sequence from Escherichia coli with MAL, SO4, PLP and GOL as ligands. Active as Phosphorylase, with EC number 2.4.1.1 Structure known Active Site: 1. Full crystallographic information is available from OCA.

Reference

Oligosaccharide substrate binding in Escherichia coli maltodextrin phosphorylase., O'Reilly M, Watson KA, Schinzel R, Palm D, Johnson LN, Nat Struct Biol. 1997 May;4(5):405-12. PMID:9145112

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