GENETIC-ANALYSIS OF ESCHERICHIA-COLI O9 RFB - IDENTIFICATION AND DNA-SEQUENCE OF PHOSPHOMANNOMUTASE AND GDP-MANNOSE PYROPHOSPHORYLASE GENES

Citation
T. Sugiyama et al., GENETIC-ANALYSIS OF ESCHERICHIA-COLI O9 RFB - IDENTIFICATION AND DNA-SEQUENCE OF PHOSPHOMANNOMUTASE AND GDP-MANNOSE PYROPHOSPHORYLASE GENES, Microbiology, 140, 1994, pp. 59-71
Citations number
38
Categorie Soggetti
Microbiology
Journal title
ISSN journal
13500872
Volume
140
Year of publication
1994
Part
1
Pages
59 - 71
Database
ISI
SICI code
1350-0872(1994)140:<59:GOEOR->2.0.ZU;2-P
Abstract
Subcloning, transposon insertion, and deletion analysis revealed that the Escherichia coli O9 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 of hybridization analysis of rfb regions of E. coli O8 and O9, and Klebsiella O3 and O5 serotypes (all of these O polysaccha rides are mannose homopolymers and the structures of the repeating uni t of E. coli O9 and Klebsiella O3 are identical) showed that a central region specific for E. coli O9 and Klebsiella O3 is flanked by two re gions common to all four. Complementation experiments using strains wi th known defects and specific tests for the enzymic activity showed th at the 50 and 55 kDa polypeptides, encoded by the common region, are p hosphomannomutase (PMM) and GDP-mannose pyrophosphorylase (GMP), respe ctively. Nucleotide sequencing of the region revealed the presence of two genes, rfbK and rfbM, analogous to the corresponding genes of Salm onella typhimurium. In E. coli O9, rfbK and rfbM encode proteins of 46 0 amino acids (50 809 Da) and 471 amino acids (52 789 Da). The amino a cid sequence of GMP was conserved in RfbMs of E. coli O7 and Salmonell a groups B, C1 and C2, CpsB of S. typhimurium, AlgA of Pseudomonas aer uginosa, and XanB of Xanthomonas campestris. The phylogenetic trees of PMM and GMP were different in topology and in the evolutionary distan ces from ancestors.