2ayh

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spinqualitylabelsall models 2ayh, resolution 1.6Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL AND MOLECULAR STRUCTURE AT 1.6 ANGSTROMS RESOLUTION OF THE HYBRID BACILLUS ENDO-1,3-1,4-BETA-D-GLUCAN 4-GLUCANOHYDROLASE H(A16-M)

Overview

H(A16-M) is a hybrid endo-1,3-1,4-beta-D-glucan 4-glucanohydrolase from Bacillus. Its crystal structure was refined using synchrotron X-ray diffraction data up to a maximal resolution of 0.16 nm. The R value of the resulting model is 14.3% against 21,032 reflections > 2 sigma. 93% of the amino acid residues are in the most favorable regions of the Ramachandran diagram, and geometrical parameters are in accordance with other proteins solved at high resolution. As shown earlier [Keitel, T., Simon, O., Borriss, R. & Heinemann, U. (1993) Proc. Natl Acad. Sci. USA 90, 5287-5291], the protein folds into a compact jellyroll-type beta-sheet structure. A systematic analysis of the secondary structure reveals the presence of two major antiparallel beta-sheets and a three-stranded minor mixed sheet. Amino acid residues involved in catalysis and substrate binding are located inside a deep channel spanning the surface of the protein. To investigate the stereochemical cause of the observed specificity of endo-1,3-1,4-beta-D-glucan 4-glucanohydrolases towards beta-1,4 glycosyl bonds adjacent to beta-1,3 bonds, the high-resolution crystal structure has been used to model an enzyme-substrate complex. It is proposed that productive substrate binding to the subsites p1, p2 and p3 of H(A16-M) requires a beta-1,3 linkage between glucose units bound to p1 and p2.

About this Structure

2AYH is a Single protein structure of sequence from Hibberdia with as ligand. This structure supersedes the now removed PDB entry 1AYH. Active as Licheninase, with EC number 3.2.1.73 Full crystallographic information is available from OCA.

Reference

Crystal and molecular structure at 0.16-nm resolution of the hybrid Bacillus endo-1,3-1,4-beta-D-glucan 4-glucanohydrolase H(A16-M)., Hahn M, Keitel T, Heinemann U, Eur J Biochem. 1995 Sep 15;232(3):849-58. PMID:7588726

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