4c2l

Publication Abstract from PubMed

Endo-Xylogalacturonan hydrolase is a member of glycoside hydrolase family 28 (GH28) that hydrolyzes the glycosidic bond between two beta-xylose substituted galacturonic acid residues in pectin. Presented here is the X-ray crystal structure of the endo-xylogalacturonan hydrolase from Aspergillus tubingensis (XghA) at 1.75 A resolution. The high degree of structural conservation in the active site and catalytic apparatus, which is shared with polygalacturonases, indicates that cleavage of the substrate proceeds in essentially the same way as found for the other GH28 enzymes. Molecular modeling of a xylosylated tri-galacturonate in the active site identified the amino acid residues involved in substrate binding. They border a substrate-binding cleft, which is much wider than in other polygalacturonases, and which can accommodate xylosylated substrates. The most extensive interactions appear to occur at subsite +2, in agreement with enzyme kinetics results, which showed enhanced activity on substrates with a xylose attached to the galacturonic acid bound in subsite +2. This article is protected by copyright. All rights reserved.

Crystal structure of Endo-Xylogalacturonan Hydrolase from Aspergillus tubingensis.,Rozeboom HJ, Beldman G, Schols HA, Dijkstra BW FEBS J. 2013 Sep 13. doi: 10.1111/febs.12524. PMID:24034788^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.