1ayx
From Proteopedia
|
CRYSTAL STRUCTURE OF GLUCOAMYLASE FROM SACCHAROMYCOPSIS FIBULIGERA AT 1.7 ANGSTROMS
Overview
The yeast Saccharomycopsis fibuligera produces a glucoamylase which, belongs to sequence family 15 of glycosyl hydrolases. The structure of the, non-glycosyl-ated recombinant enzyme has been determined by molecular, replacement and refined against 1.7 A resolution synchrotron data to an R, factor of 14.6%. This is the first report of the three-dimensional, structure of a yeast family 15 glucoamylase. The refinement from the, initial molecular-replacement model was not straightforward. It involved, the use of an unrestrained automated refinement procedure (uARP) in, combination with the maximum-likelihood refinement program REFMAC. The, enzyme consists of 492 amino-acid residues and has 14 alpha-helices, 12 of, which form an (alpha/alpha)6 barrel. It contains a single catalytic domain, but no starch-binding domain. The fold of the molecule and the active site, are compared to the known structure of the catalytic domain of a fungal, family 15 glucoamylase and are shown to be closely similar. The active-, and specificity-site residues are especially highly conserved. The model, of the acarbose inhibitor from the analysis of the fungal enzyme fits, tightly into the present structure. The active-site topology is a pocket, and hydrolysis proceeds with inversion of the configuration at the, anomeric carbon. The enzyme acts as an exo-glycosyl hydrolase. There is a, Tris [2-amino-2-(hydroxymethyl)-1,3-propanediol] molecule acting as an, inhibitor in the active-site pocket.
About this Structure
1AYX is a Single protein structure of sequence from Saccharomycopsis fibuligera with TRS as ligand. Active as Glucan 1,4-alpha-glucosidase, with EC number 3.2.1.3 Structure known Active Site: NUL. Full crystallographic information is available from OCA.
Reference
Structure of glucoamylase from Saccharomycopsis fibuligera at 1.7 A resolution., Sevcik J, Solovicova A, Hostinova E, Gasperik J, Wilson KS, Dauter Z, Acta Crystallogr D Biol Crystallogr. 1998 Sep 1;54(Pt 5):854-66. PMID:9757101
Page seeded by OCA on Mon Nov 5 15:34:59 2007
