Three-dimensional modelling of the catalytic domain of Streptococcus mutans glucosyltransferase GtfB.
Glucosyltransferases (GtfB/C/D) of Streptococcus mutans, a pathogen for human dental caries, synthesize water-insoluble glucan through the hydrolysis of sucrose. Genetic and biochemical approaches have identified several active sites of these enzymes, but no three-dimensional (3D) structural evidence is yet available to elucidate the subdomain arrangement and molecular mechanism of catalysis. Based on a combined sequence and secondary structure alignment against known crystal structures of segments from closely related proteins, we propose here the 3D model of an N-terminal domain essential for the sucrose binding and splitting in GtfB. A Tim-barrel of (alpha/beta)(8) structural characteristics is revealed and the structural correlation for two peptides is described.
Tsai
Y W
YW
Graduate Institute of Oral Biology, College of Medicine, National Taiwan University, Taipei.
Chia
J S
JS
Shiau
Y Y
YY
Chou
H C
HC
Liaw
Y C
YC
Lou
K L
KL
D000595:Amino Acid Sequence; D001665:Binding Sites; D020134:Catalytic Domain; D005964:Glucosyltransferases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D016415:Sequence Alignment; D013295:Streptococcus mutans / Q000737:chemistry / Q000201:enzymology*; D013395:Sucrose / Q000378:metabolism
D013395:Sucrose; C036655:1,3-alpha-D-glucan synthase; D005964:Glucosyltransferases