Download MendeleyThe Structural Basis for Catalysis and Specificity of the Pseudomonas Cellulosa Alpha-Glucuronidase, Glca67A
Nurizzo, D., Nagy, T., Gilbert, H.J., Davies, G.J.(2002) Structure 10: 547
- PubMed: 11937059
- DOI: https://doi.org/10.1016/s0969-2126(02)00742-6
- Primary Citation of Related Structures:
1GQI, 1GQJ, 1GQK, 1GQL - PubMed Abstract:
Alpha-glucuronidases, components of an ensemble of enzymes central to the recycling of photosynthetic biomass, remove the alpha-1,2 linked 4-O-methyl glucuronic acid from xylans. The structure of the alpha-glucuronidase, GlcA67A, from Pseudomonas cellulosa reveals three domains, the central of which is a (beta/alpha)(8) barrel housing the catalytic apparatus. Complexes of the enzyme with the individual reaction products, either xylobiose or glucuronic acid, and the ternary complex of both glucuronic acid and xylotriose reveal a "blind" pocket which selects for short decorated xylooligosaccharides substituted with the uronic acid at their nonreducing end, consistent with kinetic data. The catalytic center reveals a constellation of carboxylates; Glu292 is poised to provide protonic assistance to leaving group departure with Glu393 and Asp365 both appropriately positioned to provide base-catalyzed assistance for inverting nucleophilic attack by water.
Organizational Affiliation:
Structural Biology Laboratory, Department of Chemistry, The University of York, Heslington, United Kingdom.
