Isolation and characterization of the Streptococcus mutans gtfC gene, coding for synthesis of both soluble and insoluble glucans.
The intact gtfC gene from Streptococcus mutans GS-5 was isolated in Escherichia coli in plasmid vector pUC18. The glucosyltransferase activity expressed by the gene synthesized both low-molecular-weight water-soluble glucan and insoluble glucan in a primer-independent manner. Purification of the enzyme by procedures that minimize proteolytic digestion yielded a purified preparation with a molecular weight of 140,000. Insertional inactivation of the gtfC gene with a streptococcal erythromycin resistance gene fragment followed by transformation of strain GS-5 suggested that the gtfC gene product was required for sucrose-dependent colonization in vitro. In addition, evidence for the presence of a third gtf gene coding for soluble glucan synthesis was obtained following the construction of mutants containing deletions of both the gtfB and gtfC genes.
Hanada
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N
Department of Microbiology-Immunology, Northwestern University Medical-Dental Schools, Chicago, Illinois 60611.
Kuramitsu
H K
HK
D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial / Q000648:ultrastructure; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000235:genetics; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D005936:Glucans / Q000096:biosynthesis*; D005964:Glucosyltransferases / Q000235:genetics*; D012995:Solubility; D013295:Streptococcus mutans / Q000235:genetics*
D004269:DNA, Bacterial; D005936:Glucans; D005964:Glucosyltransferases