Identification of algI and algJ in the Pseudomonas aeruginosa alginate biosynthetic gene cluster which are required for alginate O acetylation.

摘要: Mucoid strains of Pseudomonas aeruginosa overproduce alginate, a linear exopolysaccharide Of D-mannuronate and variable amounts L-guluronate. The mannuronate residues undergo modification by C-5 epimerization to form the L-guluronates addition acetyl groups at 0-2 0-3 positions. Through genetic analysis, we previously identified algF, located upstream algA in 18-kb alginate biosynthetic operon, as gene required for acetylation. Here, show sequence 3.7-kb fragment containing open reading frames termed algI, algJ, algF. An algI::Tn5O1 mutant, which was defective algIJFA because polar nature transposon insertion, produced when provided trans. This indicated that algIJF products were not polymer biosynthesis. To examine potential role these genes modification, mutants constructed replacement each (algI, or algF) replaced gentamicin resistance cassette. Proton nuclear magnetic resonance spectroscopy showed polymers deficient still contained mixture L-guluronate, indicating affected. Alginate acetylation evaluated colorimetric assay Fourier transform-infrared spectroscopy, this analysis nonacetylated alginate. Plasmids supplied downstream affected mutations introduced into mutant. strain only algF expression an acetylated, confirming previous results. Strains missing algJ algI also alginates. Providing respective trans restored Mutants obtained chemical mutagenesis, their ability acetylate Therefore, represent newly that, are