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Identification of genes encoding glycosyltransferases involved in lipopolysaccharide synthesis in Porphyromonas gingivalis
Author(s) -
Shoji M.,
Sato K.,
Yukitake H.,
Kamaguchi A.,
Sasaki Y.,
Naito M.,
Nakayama K.
Publication year - 2018
Publication title -
molecular oral microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 77
eISSN - 2041-1014
pISSN - 2041-1006
DOI - 10.1111/omi.12200
Subject(s) - porphyromonas gingivalis , mutant , escherichia coli , complementation , biology , glycosyltransferase , gene , lipid a , virulence , biochemistry , heptose , lipopolysaccharide , glycosylation , microbiology and biotechnology , bacteria , genetics , endocrinology
Summary Porphyromonas gingivalis can synthesize both A‐LPS and O‐LPS lipopolysaccharides, which contain anionic O‐polysaccharides and conventional O‐polysaccharides, respectively. A‐LPS can anchor virulence proteins to the cell surface, so elucidating the mechanism of A‐LPS synthesis is important for understanding the pathogenicity of this bacterium. To identify the genes involved in LPS synthesis, we focused on uncharacterized genes encoding the glycosyltransferases, PGN_0361, PGN_1239, PGN_1240 and PGN_1668, which were tentatively named gtfC , gtfD , gtfE and gtfF , respectively, and characterized their mutants. We found that disruption of gtfC and gtfF resulted in A‐LPS deficiency. In addition, a gtfD mutant had abnormal A‐LPS synthesis, and a gtfE mutant exhibited a rough‐type LPS that possesses a short oligosaccharide with lipid A‐core. We then constructed a gtfC and gtfD double mutant, because their amino acid sequences were very similar, and this mutant similarly possessed a rough‐type LPS. Cross‐complementation analysis revealed that the GtfD protein is a functional homologue of the Escherichia coli WbbL protein, which is a rhamnosyltransferase. These results suggested that the GtfE protein is essential for the synthesis of both O‐LPS and A‐LPS, and that GtfC and GtfD proteins may work together to synthesize the two kinds of LPS. In addition, the GtfF protein was essential for A‐LPS synthesis, although this may be achieved in a strain‐specific manner.