title: Knowledge-based model of a glucosyltransferase from the oral bacterial group of mutans streptococci.
abstract: Mutans streptococci glucosyltransferases catalyze glucosyl transfer from sucrose to a glucan chain. We previously identified an aspartyl residue that participates in stabilizing the glucosyl transition state. The sequence surrounding the aspartate was found to have substantial sequence similarity with members of alpha-amylase family. Because little is known of the protein structure beyond the amino acid sequence, we used a knowledge-based interactive algorithm, MACAW, which provided significant level of homology with alpha-amylases and glucosyltransferase from Streptococcus downei gtfI (GTF). The significance of GTF similarity is underlined by GTF/alpha-amylase residues conserved in all but one alpha-amylase invariant residues. Site-directed mutagenesis of the three GTF catalytic residues are homologous with the alpha-amylase catalytic triad. The glucosyltransferases are members of the 4/7-superfamily that have a (beta/alpha)8-barrel structure and belong to family 13 of the glycohydralases.
authors.affiliation: Department of Basic Sciences, School of Dentistry, University of Southern California, Los Angeles 90089-0641, USA.
authors.forename: K S
authors.initials: KS
authors.lastname: Devulapalle
authors.forename: S D
authors.initials: SD
authors.lastname: Goodman
authors.forename: Q
authors.initials: Q
authors.lastname: Gao
authors.forename: A
authors.initials: A
authors.lastname: Hemsley
authors.forename: G
authors.initials: G
authors.lastname: Mooser
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D003198:Computer Simulation; D003460:Crystallization; D005964:Glucosyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008956:Models, Chemical; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D012984:Software; D013295:Streptococcus mutans / Q000201:enzymology*; D000516:alpha-Amylases / Q000737:chemistry
chemical_list: D005964:Glucosyltransferases; D000516:alpha-Amylases