Function and structure of Streptococus sobrinus glucosyltransferase responsible for water-soluble glucan synthesis

1993 Fiscal Year Final Research Report Summary

• Project/Area Number: 04671100
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Morphological basic dentistry
• Research Institution: Okayama University
• Principal Investigator: FUKUI Kazuhiro Okayama University, Dental School, Professor, 歯学部, 教授 (70034171)
• Co-Investigator(Kenkyū-buntansha): OHTA Hiroyuki Okayama University, Dental School, Associate Professor, 歯学部, 助教授 (80168947)
• Project Period (FY): 1992 – 1993
• Keywords: Streptococcous cricetus / glucosyltransferase / cloning GTF gene / water-soluble glucan synthesis

Research Abstract

Streptococcus cricetus has four kinds of glucosyltransferase (GTFs), i.e.GTF-I,GTF-S,GTF-SI and GTF-T.These enzymes co-operatively synthesize adhesive water-insoluble glucan from sucrose, which contributes firm adherence of growing organisms to smooth dental surfaces.
In this study, the genes encoding glucosyltransferase reponsible for water-soluble glucan synthesis (GTF-S and GTF-T) of S.cricetus HS-6 were cloned. THe sequence of GTF-S genes from S.cricetus and S.downei were compered and show a high degree of homology. There is a 73.9% homology of nucleotides in the genes, and 77.4% homology of amino acids in the deduced protein sequences. In comparison of GTF-T genes with S.cricetus and S.sobrinus, there is 79.7% homology in the genes, and 83.5% homology in the deduced protein sequences.
The availability of recombinant E.coli carrying the these genes will greatly facilitate purification of the enzymes for biochemical studies.