Cloning of Pseudomonas aeruginosa algG, which controls alginate structure.

摘要: The biochemical mechanism by which alpha-L-guluronate (G) residues are incorporated into alginate Pseudomonas aeruginosa is not understood. P. first synthesizes GDP-mannuronate, used to incorporate beta-D-mannuronate the polymer. It likely that conversion of some G occurs action a C-5 epimerase at either monomer (e.g., sugar-nucleotide) or polymer level. This study describes results molecular genetic approach identify gene involved in formation incorporation aeruginosa. Mucoid FRD1 was chemically mutagenized, and mutants FRD462 FRD465, were incapable incorporating alginate, independently isolated. Assays using G-specific lyase from Klebsiella aerogenes 1H-nuclear magnetic resonance analyses showed absent alginates secreted these mutants. also wild-type contained no detectable blocks G. mutations responsible for defective FRD465 designated algG4 algG7, respectively. Genetic mapping experiments revealed algG closely linked (greater than 90%) argF, lies 34 min on chromosome adjacent cluster genes required biosynthesis. clone pALG2, 35 kilobases DNA included argF alleles, identified bank screening method replacement. A fragment carrying shown complement algG7 trans. physically mapped subcloning Tn501 mutagenesis.