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Knowledge‐based model of a glucosyltransferase from the oral bacterial group of mutans streptococci
Author(s) -
Devulapalle Kumari S.,
Goodman Steven D.,
Gao Qian,
Hemsley Ann,
Mooser Gregory
Publication year - 1997
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560061201
Subject(s) - glucosyltransferase , glucosyltransferases , biochemistry , streptococcus mutans , streptococcus sobrinus , biology , amylase , homology (biology) , peptide sequence , sequence alignment , enzyme , amino acid , bacteria , genetics , gene
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 α‐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 α‐amylases and glucosyltransferase from Streptococcus downei gtfI (GTF). The significance of GTF similarity is underlined by GTF/α‐amylase residues conserved in all but one α‐amylase invariant residues. Site‐directed mutagenesis of the three GTF catalytic residues are homologous with the α‐amylase catalytic triad. The glucosyltransferases are members of the 4/7‐superfamily that have a (β/α) 8 ‐barrel structure and belong to family 13 of the glycohydralases.