1gah

From Proteopedia

Revision as of 06:27, 30 October 2007

GLUCOAMYLASE-471 COMPLEXED WITH ACARBOSE

Overview

Crystal structures at pH 4 of complexes of glucoamylase from Aspergillus, awamori var. X100 with the pseudotetrasaccharides D-gluco-dihydroacarbose, and acarbose have been refined to R-factors of 0.147 and 0.131 against, data to 1.7- and 2.0-A resolution, respectively. The two inhibitors bind, in nearly identical manners, each exhibiting a dual binding mode with, respect to the location of the last sugar residues. The reduced affinity, of D-gluco-dihydroacarbose (K1 = 10(-8) M) relative to acarbose (K1 =, 10(-12) M) may stem in part from the weakening of hydrogen bonds of the, catalytic water (Wat 500) to the enzyme. Steric contacts between the, nonreducing end of D-gluco-dihydroacarbose and the catalytic water perturb, Wat 500 from its site of optimal hydrogen bonding to the active ... [(full description)]

About this Structure

1GAH is a [Single protein] structure of sequence from [Aspergillus awamori] with MAN, ACR, SER and GLY as [ligands]. Active as [Hydrolase], with EC number [3.2.1.3]. Structure known Active Sites: SB1, SB2 and SB3. Full crystallographic information is available from [OCA].

Reference

Crystallographic complexes of glucoamylase with maltooligosaccharide analogs: relationship of stereochemical distortions at the nonreducing end to the catalytic mechanism., Aleshin AE, Stoffer B, Firsov LM, Svensson B, Honzatko RB, Biochemistry. 1996 Jun 25;35(25):8319-28. PMID:8679589

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