title: Membrane topology of outer membrane protein AlgE, which is required for alginate production in Pseudomonas aeruginosa.
abstract: The ubiquitous opportunistic human pathogen Pseudomonas aeruginosa secretes a viscous extracellular polysaccharide, called alginate, as a virulence factor during chronic infection of patients with cystic fibrosis. In the present study, it was demonstrated that the outer membrane protein AlgE is required for the production of alginate in P. aeruginosa. An isogenic marker-free algE deletion mutant was constructed. This strain was incapable of producing alginate but did secrete alginate degradation products, indicating that polymerization occurs but that the alginate chain is subsequently degraded during transit through the periplasm. Alginate production was restored by introducing the algE gene. The membrane topology of the outer membrane protein AlgE was assessed by site-specific insertions of FLAG epitopes into predicted extracellular loop regions.
authors.affiliation: Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North, New Zealand.
authors.forename: Iain D
authors.initials: ID
authors.lastname: Hay
authors.forename: Zahid U
authors.initials: ZU
authors.lastname: Rehman
authors.forename: Bernd H A
authors.initials: BH
authors.lastname: Rehm
mesh_terms: D000464:Alginates / Q000378:metabolism*; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D017353:Gene Deletion; D005816:Genetic Complementation Test; D020723:Glucuronic Acid / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D011550:Pseudomonas aeruginosa / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000464:Alginates; D001425:Bacterial Outer Membrane Proteins; D006603:Hexuronic Acids; D020723:Glucuronic Acid