1wd3
From Proteopedia
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 ConservationCheck, 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
|