1wd3
Crystal structure of arabinofuranosidase
Structural highlights
FunctionABFB_ASPKW Alpha-L-arabinofuranosidase involved in the degradation of arabinoxylan, a major component of plant hemicellulose. Able to hydrolyze 1,5-, 1,3- and 1,2-alpha-linkages not only in L-arabinofuranosyl oligosaccharides, but also in polysaccharides containing terminal non-reducing L-arabinofuranoses in side chains, like L-arabinan, arabinogalactan and arabinoxylan.[1] [2] 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 PubMedAs the first known structures of a glycoside hydrolase family 54 (GH54) enzyme, we determined the crystal structures of free and arabinose-complex forms of Aspergillus kawachii IFO4308 alpha-l-arabinofuranosidase (AkAbfB). AkAbfB comprises two domains: a catalytic domain and an arabinose-binding domain (ABD). The catalytic domain has a beta-sandwich fold similar to those of clan-B glycoside hydrolases. ABD has a beta-trefoil fold similar to that of carbohydrate-binding module (CBM) family 13. However, ABD shows a number of characteristics distinctive from those of CBM family 13, suggesting that it could be classified into a new CBM family. In the arabinose-complex structure, one of three arabinofuranose molecules is bound to the catalytic domain through many interactions. Interestingly, a disulfide bond formed between two adjacent cysteine residues recognized the arabinofuranose molecule in the active site. From the location of this arabinofuranose and the results of a mutational study, the nucleophile and acid/base residues were determined to be Glu(221) and Asp(297), respectively. The other two arabinofuranose molecules are bound to ABD. The O-1 atoms of the two arabinofuranose molecules bound at ABD are both pointed toward the solvent, indicating that these sites can both accommodate an arabinofuranose side-chain moiety linked to decorated arabinoxylans. Crystal structure of a family 54 alpha-L-arabinofuranosidase reveals a novel carbohydrate-binding module that can bind arabinose.,Miyanaga A, Koseki T, Matsuzawa H, Wakagi T, Shoun H, Fushinobu S J Biol Chem. 2004 Oct 22;279(43):44907-14. Epub 2004 Aug 3. PMID:15292273[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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