The gtfS gene, coding for a glucosyltransferase which synthesizes water-soluble glucan and previously cloned from Streptococcus downei strain MFe28 (mutans serotype h) into a bacteriophage vector, was subcloned into a plasmid vector. The gtfS gene products expressed in Escherichia coli were compared to the primer-independent, oligo-isomaltosaccharide synthase in Streptococcus sobrinus strain AHT (mutans serotype g) and shown to resemble it closely in molecular mass, isoelectric point, immunological properties, optimum pH and K(m) values. The glucans produced from sucrose by the gtfS gene products are α-1,6-linked linear oligo-isomaltosaccharides without any branching sites. A similar gtfS gene was also detected on chromosomal DNA from S. sobrinus strain AHT.
All Science Journal Classification (ASJC) codes