Sequence and phylogenetic analyses of the water‐soluble glucan synthesizing‐glucosyltransferase genes of Streptococcus dentirousetti

Abstract

Two tandemly aligned glucosyltransferase (GTF) genes whose gene products are responsible for watersoluble glucan synthesis were isolated from Streptococcus dentirousetti NUM1303 and sequenced. One of the GTF genes of S. dentirousetti consisted of a 4110 bp open reading frame (ORF) that encoded for a 1369 amino acid protein and was revealed to be a S. sobrinus gtfS homolog. The percent similarity of amino acid sequences of the GTF-S from S. dentirousetti compared to those from S. sobrinus was 99%. In addition, a putative gtfT was found in tandem in the downstream region of the S. dentirousetti gtfS. The gtfTof S. dentirousetti consisted of a 4527 bp ORF encoding for 1508 amino acids. The similarity of amino acid sequences of the GTF-T from S. dentirousetti and S. sobrinus was 94%. Phylogenetic analysis based on amino acid sequences from other related streptococcal GTFs suggested that both GTF-S and GTF-T of S. dentirousetti are closely related to S. sobrinus.

An Update on the Evolution of Glucosyltransferase (Gtf) Genes in Streptococcus

“…Specifically, two Downei group species, S. downei and S. sobrinus , have been reported to produce four different types of Gtf enzymes encoded by genes GtfI, GtfS, GtfT , and GtfU (Ferretti et al, 1987; Yamashita et al, 1989; Gilmore et al, 1990; Abo et al, 1991; Hanada et al, 1993, 2002; Colby et al, 1999). Two of these genes, GtfS and GtfT , were also found arranged in tandem on chromosomes in S. criceti and S. dentirousetti (Inoue et al, 2000; Shinozaki-Kuwahara et al, 2013). Moreover, four different Gtf genes, namely GtfJ, GtfK, GtfL , and GtfM , were identified in S. salivarius ATCC 25975 (Giffard et al, 1991, 1993; Simpson et al, 1995b).…”