1bfn

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Revision as of 09:29, 20 November 2007

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spinqualitylabelsall models 1bfn, resolution 2.07Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

BETA-AMYLASE/BETA-CYCLODEXTRIN COMPLEX

Overview

In order to study the interaction of soybean beta-amylase with substrate, we solved the crystal structure of beta-cyclodextrin-enzyme complex and, compared it with that of alpha-cyclodextrin-enzyme complex. The enzyme was, expressed in Escherichia coli at a high level as a soluble and, catalytically active protein. The purified recombinant enzyme had, properties nearly identical to those of native soybean beta-amylase and, formed the same crystals as the native enzyme. The crystal structure of, recombinant enzyme complexed with beta-cyclodextrin was refined at 2. 07-A, resolution with a final crystallographic R value of 15.8% (Rfree = 21.1%)., The root mean square deviation in the position of C-alpha atoms between, this recombinant enzyme and the native enzyme was 0.22 A. These results, indicate that the expression system established here is suitable for, studying structure-function relationships of beta-amylase. The, conformation of the bound beta-cyclodextrin takes an ellipsoid shape in, contrast to the circular shape of the bound alpha-cyclodextrin. The, cyclodextrins shared mainly two glucose binding sites, 3 and 4. The, glucose residue 4 was slightly shifted from the maltose binding site. This, suggests that the binding site of the cyclodextrins is important for its, holding of a cleaved substrate, which enables the multiple attack, mechanism of beta-amylase.

About this Structure

1BFN is a Single protein structure of sequence from Glycine max with SO4 as ligand. Active as Beta-amylase, with EC number 3.2.1.2 Full crystallographic information is available from OCA.

Reference

Crystal structure of recombinant soybean beta-amylase complexed with beta-cyclodextrin., Adachi M, Mikami B, Katsube T, Utsumi S, J Biol Chem. 1998 Jul 31;273(31):19859-65. PMID:9677422

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