GDPmannose dehydrogenase and biosynthesis of alginate-like polysaccharide in a mucoid strain of Pseudomonas aeruginosa

Abstract

GDPmannose dehydrogenase (EC 1.1.1.132) in a mucoid strain of Pseudomonas aeruginosa isolated from a patient with cystic fibrosis was identified by demonstrating the NAD-linked formation of GDPmannuronate from GDPmannose mediated by a cell extract of the organism. Nonmucoid mutant strains did not contain GDPmannose dehydrogenase, which suggests that the enzyme is involved in the biosynthesis of alginate-like polysaccharide by P. aeruginosa.

Alginate synthesis by Pseudomonas aeruginosa: a key pathogenic factor in chronic pulmonary infections of cystic fibrosis patients.

“…The activities of these four enzymes (PMI, PMM, GMP, and GMD) are either absent or greatly reduced in nonmucoid strains compared with the low levels in mucoid strains of P. aeruginosa (124,127). Similar results have been obtained by our laboratory (2,25,139,142) and others (129), suggesting that low enzymatic activities are a general characteristic of alginate biosynthetic enzymes even in the most highly mucoid strains of P. aeruginosa.…”

Cloning of Escherichia coli and Pseudomonas aeruginosa phosphomannose isomerase genes and their expression in alginate-negative mutants of Pseudomonas aeruginosa

“…This group was able to demonstrate the presence of enzymes required to synthesize GDP-mannuronic acid. Recently, also in support of the proposed pathway, Pugashetti et al (36) indicated that GDP-mannose may be an intermediate in alginate biosynthesis by P. aeruginosa. We have described here the cloning and identification of a gene directly involved in the synthesis of alginic acid by P. aeruginosa.…”

“…GDP-mannose is then oxidized by GDP-mannose dehydrogenase to GDP-mannuronic acid, and alginic acid is then formed after polymerization of the mannuronic acid residues, epimerization of some of the mannuronic acid residues to guluronic acid, and acetylation. Whereas the overall pathway of alginate synthesis by P. aeruginosa has yet to be elucidated, Pugashetti et al (36) have presented evidence to suggest that GDP-mannose dehydrogenase is required for the biosynthesis of alginate. However, Banerjee et al (3) have reported on the virtual absence of PMI activity in the cell-free extracts of several independent mucoid and nonmucoid bacteria.…”

Influence of macrolides on mucoid alginate biosynthetic enzyme from Pseudomonas aeruginosa

“…The alginate biosynthetic pathway in mucoid P. aeruginosa has been demonstrated to involve phosphomannose isomerase (PMI) [30,31], phosphomannomutase (PMM) [30,31], guanosine diphospho‐D‐mannose pyrophosphorylase (GMP) [30,31], GDP‐mannose dehydrogenase [30,31], epimerase [32,33], polymerase [34] and acetylase [35] (Figure 6). The first four enzymes (PMI, PMM, GMP and GDP‐mannose dehydrogenase) of alginate biosynthesis are detected in mucoid P. aeruginosa but not in the non‐mucoid form [36]. The enzymatic activity of GDP‐mannose dehydrogenase is significantly higher than that of other enzymes in mucoid strains [37].…”