Summary: Subcloning, transposon insertion, and deletion analysis revealed that the 09 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 regions of 08 and 09, and 03 and 05 serotypes (all of these O polysaccharides are mannose homopolymers and the structures of the repeating unit of 09 and 03 are identical) showed that a central region specific for 09 and 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, and , analogous to the corresponding genes of . In 09, and 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 07 and B, C1 and C2, CpsB of , AlgA of , and XanB of . The phylogenetic trees of PMM and GMP were different in topology and in the evolutionary distances from ancestors.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error