Structural highlights
Publication Abstract from PubMedalpha-l-Fucosidase isoenzyme 1 from bacterium Paenibacillus thiaminolyticus is a member of the glycoside hydrolase family GH29 capable of cleaving l-fucose from nonreducing termini of oligosaccharides and glycoconjugates. Here we present the first crystal structure of this protein revealing a novel quaternary state within this family. The protein is in a unique hexameric assembly revealing the first observed case of active site complementation by a residue from an adjacent monomer in this family. Mutation of the complementing tryptophan residue caused changes in the catalytic properties including a shift of the pH optimum, a change of affinity to an artificial chromogenic substrate and a decreased reaction rate for a natural substrate. The wild-type enzyme was active on most of the tested naturally occurring oligosaccharides and capable of transglycosylation on a variety of acceptor molecules, including saccharides, alcohols or chromogenic substrates. Mutation of the complementing residue changed neither substrate specificity nor the preference for the type of transglycosylation acceptor molecule; however, the yields of the reactions were lower in both cases. Maltose molecules bound to the enzyme in the crystal structure identified surface carbohydrate-binding sites, possibly participating in binding of larger oligosaccharides. Active site complementation and hexameric arrangement in the GH family 29; a structure-function study of alpha-l-fucosidase isoenzyme 1 from Paenibacillus thiaminolyticus.,Kovalova T, Koval T, Benesova E, Vodickova P, Spiwok V, Lipovova P, Dohnalek J Glycobiology. 2019 Jan 1;29(1):59-73. doi: 10.1093/glycob/cwy078. PMID:30544181[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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