Genetic analysis of Escherichia coli 09 rfb: identification and DNA sequence of phosphomannomutase and GDP-mannose pyrophosphorylase genes
| Autor: | Barbara Jann, Atsushi Saeki, Michio Ohta, Nobuo Kato, Klaus Jann, Tsuyoshi Sugiyama, Nobuo Kido, Takayuki Komatsu |
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| Rok vydání: | 1994 |
| Předmět: | |
| Zdroj: | Microbiology. 140:59-71 |
| ISSN: | 1465-2080 1350-0872 |
| DOI: | 10.1099/13500872-140-1-59 |
| Popis: | Summary: Subcloning, transposon insertion, and deletion analysis revealed that the Escherichia coli 09 rfb region is about 12 kb in size. The region encodes at least seven polypeptides of 89, 74, 55, 50, 44, 41 and 39·5 kDa. Southern hybridization analysis of rfb regions of E. coli 08 and 09, and Klebsiella 03 and 05 serotypes (all of these O polysaccharides are mannose homopolymers and the structures of the repeating unit of E. coli 09 and Klebsiella 03 are identical) showed that a central region specific for E. coli 09 and Klebsiella 03 is flanked by two regions common to all four. Complementation experiments using strains with known defects and specific tests for the enzymic activity showed that the 50 and 55 kDa polypeptides, encoded by the common region, are phosphomannomutase (PMM) and GDP-mannose pyrophosphorylase (GMP), respectively. Nucleotide sequencing of the region revealed the presence of two genes, rfbK and rfbM, analogous to the corresponding genes of Salmonella typhimurium. In E. coli 09, rfbK and rfbM encode proteins of 460 amino acids (50809 Da) and 471 amino acids (52 789 Da). The amino acid sequence of GMP was conserved in RfbMs of E. coli 07 and Salmonella groups B, C1 and C2, CpsB of S. typhimurium, AlgA of Pseudomonas aeruginosa, and XanB of Xanthomonas campestris. The phylogenetic trees of PMM and GMP were different in topology and in the evolutionary distances from ancestors. |
| Databáze: | OpenAIRE |
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