Genetic organisation and evolution of Yersinia pseudotuberculosis 3,6-dideoxyhexose biosynthetic genes.
3,6-dideoxyhexose (DDH) sugars occur in some of the O antigens of Salmonella enterica and Yersinia pseudotuberculosis, but are otherwise rarely found in nature. Y. pseudotuberculosis DDH biosynthetic genes rfbS (encoding CDP-paratose synthetase) and rfbE (encoding CDP-tyvelose epimerase) were amplified and cloned, and their sequences determined. Comparisons with the equivalent genes of S. enterica show that the genetic arrangement of DDH genes is very similar; however, in Y. pseudotuberculosis there is no suggestion that paratose producing strains are derived from tyvelose-producing strains by inactivation of rfbE, which is the case in S. enterica. The previously determined DNA sequence of the rfb region of an abequose-producing strain was re-examined. It contains the remnants of an insertion sequence (IS) adjacent to a truncated and non-functional rfbE gene. This suggests that the IS was involved in recombination events contributing to O-antigen antigenic diversity in Y. pseudotuberculosis.
Department of Microbiology, University of Sydney, NSW, Australia.
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M
Hobbs
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PR
Reeves
D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D019143:Evolution, Molecular; D006601:Hexoses / Q000235:genetics*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017421:Sequence Analysis; D015011:Yersinia pseudotuberculosis / Q000201:enzymology / Q000235:genetics*
D006601:Hexoses; C009616:tyvelose