1h8v
THE X-RAY CRYSTAL STRUCTURE OF THE TRICHODERMA REESEI FAMILY 12 ENDOGLUCANASE 3, CEL12A, AT 1.9 A RESOLUTION
OverviewOverview
We present the three-dimensional structure of Trichoderma reesei endoglucanase 3 (Cel12A), a small, 218 amino acid residue (24.5 kDa), neutral pI, glycoside hydrolase family 12 cellulase that lacks a cellulose-binding module. The structure has been determined using X-ray crystallography and refined to 1.9 A resolution. The asymmetric unit consists of six non-crystallographic symmetry-related molecules that were exploited to improve initial multiple isomorphous replacement phasing, and subsequent structure refinement. The enzyme contains one disulfide bridge and is glycosylated at Asp164 by a single N-acetyl glucosamine residue. The protein has the expected fold for a glycoside hydrolase clan-C family 12 enzyme. It contains two beta-sheets, of six and nine strands, packed on top of one another, and one alpha-helix. The concave surface of the nine-stranded beta-sheet forms a large substrate-binding groove in which the active-site residues are located. In the active site, we find a carboxylic acid trio, similar to that of glycoside hydrolase families 7 and 16. The strictly conserved Asp99 hydrogen bonds to the nucleophile, the invariant Glu116. The binding crevice is lined with both aromatic and polar amino acid side-chains which may play a role in substrate binding. The structure of the fungal family 12 enzyme presented here allows a complete structural characterization of the glycoside hydrolase-C clan.
About this StructureAbout this Structure
1H8V is a Single protein structure of sequence from Hypocrea jecorina. Full crystallographic information is available from OCA.
ReferenceReference
The X-ray crystal structure of the Trichoderma reesei family 12 endoglucanase 3, Cel12A, at 1.9 A resolution., Sandgren M, Shaw A, Ropp TH, Wu S, Bott R, Cameron AD, Stahlberg J, Mitchinson C, Jones TA, J Mol Biol. 2001 Apr 27;308(2):295-310. PMID:11327768 Page seeded by OCA on Fri May 2 18:34:51 2008