1gqk
From Proteopedia
Structure of Pseudomonas cellulosa alpha-D-glucuronidase complexed with glucuronic acid
Structural highlights
Function[AGUA_CELJU] Alpha-glucuronidase involved in the hydrolysis of xylan, a major structural heterogeneous polysaccharide found in plant biomass representing the second most abundant polysaccharide in the biosphere, after cellulose. It catalyzes the cleavage of the alpha-1,2-glycosidic bond at the non-reducing end of 4-O-methyl-D-glucuronic acid (4-O-MeGlcA) side chain of short xylooligosaccharides and releases 4-O-methylglucuronic acid. It can also hydrolyze small soluble oligosaccharides such as dobiouronic acid, aldotriouronic acid, aldotetraouronic acid, and aldopentaouronic acid.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedAlpha-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. The structural basis for catalysis and specificity of the Pseudomonas cellulosa alpha-glucuronidase, GlcA67A.,Nurizzo D, Nagy T, Gilbert HJ, Davies GJ Structure. 2002 Apr;10(4):547-56. PMID:11937059[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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