title: Site-specific activity of the acyltransferases HtrB1 and HtrB2 in Pseudomonas aeruginosa lipid A biosynthesis.
abstract: Pseudomonas aeruginosa (PA) is an opportunistic Gram-negative pathogen associated with nosocomial infections, acute infections and chronic lung infections in patients with cystic fibrosis. The ability of PA to cause infection can be attributed to its ability to adapt to a multitude of environments. Modification of the lipid A portion of lipopolysaccharide (LPS) is a vital mechanism Gram-negative pathogens use to remodel the outer membrane in response to environmental stimuli. Lipid A, the endotoxic moiety of LPS, is the major component of the outer leaflet of the outer membrane of Gram-negative bacteria making it a critical factor for bacterial adaptation. One way PA modifies its lipid A is through the addition of laurate and 2-hydroxylaurate. This secondary or late acylation is carried out by the acyltransferase, HtrB (LpxL). Analysis of the PA genome revealed the presence of two htrB homologs, PA0011 (htrB1) and PA3242 (htrB2). In this study, we were able to show that each gene identified is responsible for site-specific modification of lipid A. Additionally, deletions of either gene altered resistance to specific classes of antibiotics, cationic antimicrobial peptides and increased membrane permeability suggesting a role for these enzymes in maintaining optimal membrane organization and integrity.
authors.affiliation: Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Hittle
authors.affiliation: Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Powell
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA 98195, USA.
authors.forename: Jace W
authors.initials: JW
authors.lastname: Jones
authors.affiliation: Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA.
authors.forename: Majid
authors.initials: M
authors.lastname: Tofigh
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA 98195, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Goodlett
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA 98195, USA Department of Pediatrics, Massachusetts General Hospital, Boston, MA 20114, USA.
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Moskowitz
authors.affiliation: Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD 21201, USA rkernst@umaryland.edu.
authors.forename: Robert K
authors.initials: RK
authors.lastname: Ernst
mesh_terms: D000215:Acylation; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D006801:Humans; D007848:Laurates / Q000378:metabolism; D008050:Lipid A / Q000096:biosynthesis*; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D007848:Laurates; D008050:Lipid A; D000217:Acyltransferases; C118473:LpxL protein, bacteria
keywords: HtrB; LPS; Pseudomonas aeruginosa; acyltransferase; lipid A; membrane remodeling