Fucosyltransferases: structure/function studies

alpha3-fucosyltransferases. (alpha3-FucTs) catalyze the final step in the s ynthesis of a range of important glycoconjugates that function in cell adhe sion and lymphocyte recirculation. Six members of this family of enzymes ha ve been cloned from the human genome, and their expression pattern has been shown to be highly regulated. Each enzyme has a unique acceptor substrate binding pattern, and each generates a unique range of fucosylated products. Results from a range of studies have provided information on amino acids i n the FucT sequence that contribute to the differential acceptor specificit y for the FucTs, and to the binding of the nucleotide sugar donor GDP-fucos e. These results, in conjunction with results obtained from the analysis of the disulfide bond pattern, have provided useful clues about the spatial d istribution of amino acids that influence or directly contribute to substra te binding. This information is reviewed here, and a molecular fold predict ion is presented which has been constructed based on the available informat ion and current modeling methodology.