Structural highlights
Function
[3XYN1_VIBSX] Catalyzes the hydrolysis of beta-1,3-xylan into oligosaccharides, mainly xylobiose, xylotriose and xylotetraose. Converts beta-1,3-xylotriose into xylose and xylobiose, converts beta-1,3-xylotetraose mainly into xylotriose and xylose, converts beta-1,3-xylopentaose into xylobiose and xylotriose. Does not hydrolyze beta-1,4-xylan, beta-1,4-mannan, beta-1,4-glucan, beta-1,3-xylobiose or p-nitrophenyl-beta-xyloside.[1]
Publication Abstract from PubMed
Xylanases capable of degrading the crystalline microfibrils of 1,3-xylan that reinforce the cell walls of some red and siphonous green algae have not been well studied, yet they could prove to be of great utility in algaculture for the production of food and renewable chemical feedstocks. To gain a better mechanistic understanding of these enzymes, a suite of reagents was synthesized and evaluated as substrates and inhibitors of an endo-1,3-xylanase. With these reagents, a retaining mechanism was confirmed for the xylanase, its catalytic nucleophile identified, and the existence of -3 to +2 substrate-binding subsites demonstrated. Protein crystal X-ray diffraction methods provided a high resolution structure of a trapped covalent glycosyl-enzyme intermediate, indicating that the 1,3-xylanases likely utilize the (1)S(3) --> (4)H(3) --> (4)C(1) conformational itinerary to effect catalysis.
Mechanistic insights into the 1,3-xylanases: useful enzymes for manipulation of algal biomass.,Goddard-Borger ED, Sakaguchi K, Reitinger S, Watanabe N, Ito M, Withers SG J Am Chem Soc. 2012 Feb 29;134(8):3895-902. doi: 10.1021/ja211836t. Epub 2012 Feb, 16. PMID:22296113[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Kiyohara M, Sakaguchi K, Yamaguchi K, Araki T, Nakamura T, Ito M. Molecular cloning and characterization of a novel beta-1,3-xylanase possessing two putative carbohydrate-binding modules from a marine bacterium Vibrio sp. strain AX-4. Biochem J. 2005 Jun 15;388(Pt 3):949-57. PMID:15743273 doi:http://dx.doi.org/10.1042/BJ20050190
- ↑ Goddard-Borger ED, Sakaguchi K, Reitinger S, Watanabe N, Ito M, Withers SG. Mechanistic insights into the 1,3-xylanases: useful enzymes for manipulation of algal biomass. J Am Chem Soc. 2012 Feb 29;134(8):3895-902. doi: 10.1021/ja211836t. Epub 2012 Feb, 16. PMID:22296113 doi:http://dx.doi.org/10.1021/ja211836t
