2AYH

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)

Replaces:  1AYH

Summary for 2AYH

• Entry DOI: 10.2210/pdb2ayh/pdb
• Descriptor: 1,3-1,4-BETA-D-GLUCAN 4-GLUCANOHYDROLASE, CALCIUM ION (3 entities in total)
• Functional Keywords: hydrolase (glucanase)
• Biological source: hybrid
• Total number of polymer chains: 1
• Total formula weight: 23975.31

Authors

Hahn, M.,Keitel, T.,Heinemann, U. (deposition date: 1995-02-02, release date: 1995-03-31, Last modification date: 2024-10-23)

Primary citation

Hahn, M.,Keitel, T.,Heinemann, U.
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).
Eur.J.Biochem., 232:849-858, 1995

PubMed Abstract: 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.

PubMed: 7588726
DOI: 10.1111/j.1432-1033.1995.tb20883.x

Experimental method

X-RAY DIFFRACTION (1.6 Å)