1urx

From Proteopedia

Revision as of 15:04, 5 November 2007

CRYSTALLOGRAPHIC STRUCTURE OF BETA-AGARASE A IN COMPLEX WITH OLIGOAGAROSE

Overview

Agarose is a gel-forming polysaccharide with an, alpha-L(1,4)-3,6-anhydro-galactose, beta-D(1,3)-galactose repeat unit, from the cell walls of marine red algae. beta-agarase A, from the, Gram-negative bacterium Zobellia galactanivorans, is secreted to the, external medium and degrades agarose with an endo-mechanism. The structure, of the inactive mutant beta-agarase A-E147S in complex with agaro-octaose, has been solved at 1.7 A resolution. Two oligosaccharide chains are bound, to the protein. The first one resides in the active site channel, spanning, subsites -4 to -1. A second oligosaccharide binding site, on the opposite, side of the protein, was filled with eight sugar units, parallel to the, active site. The crystal structure of the beta-agarase A with, agaro-octaose provides detailed information on agarose recognition in the, catalytic site. The presence of the second, parallel, binding site, suggests that the enzyme might be able to unwind the double-helical, structure of agarose prior to the catalytic cleavage.

About this Structure

1URX is a Single protein structure of sequence from Zobellia galactanivorans with CA as ligand. Active as Beta-agarase, with EC number 3.2.1.81 Structure known Active Site: AC1. Full crystallographic information is available from OCA.

Reference

Parallel substrate binding sites in a beta-agarase suggest a novel mode of action on double-helical agarose., Allouch J, Helbert W, Henrissat B, Czjzek M, Structure. 2004 Apr;12(4):623-32. PMID:15062085

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