Resistance Phenotypes Mediated by Aminoacyl-Phosphatidylglycerol Synthases

• Published in: Journal of Bacteriology Vol. 194; no. 6; pp. 1401 - 1416
• Main Authors: Arendt, Wiebke, Hebecker, Stefanie, Jäger, Sonja, Nimtz, Manfred, Moser, Jürgen
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.03.2012
• Subjects: alanine; Alanine - metabolism; amino acid sequences; aminoacylation; Aminoacyltransferases - genetics; Aminoacyltransferases - metabolism; Anti-Bacterial Agents - pharmacology; antibiotics; antimicrobial cationic peptides; Bacterial proteins; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; beta-lactams; Biochemistry; Biological and medical sciences; chimerism; Drug resistance; Drug Resistance, Bacterial; enzymes; evolution; Fundamental and applied biological sciences. Psychology; Genotype & phenotype; Gram-negative bacteria; lipopeptides; lysine; Lysine - metabolism; Microbial Sensitivity Tests; Microbiology; Miscellaneous; mutants; phenotype; Phosphatidylglycerols - metabolism; phospholipids; Phylogeny; Polypeptides; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - enzymology; Pseudomonas aeruginosa - genetics; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Sequence Homology, Amino Acid; Resistance; Phenotype; Synthase; Enzyme
• ISSN: 0021-9193; 1098-5530; 1067-8832
• DOI: 10.1128/JB.06576-11

The specific aminoacylation of the phospholipid phosphatidylglycerol (PG) with alanine or with lysine catalyzed by aminoacyl-phosphatidylglycerol synthases (aaPGS) was shown to render various organisms less susceptible to antibacterial agents. This study makes use of Pseudomonas aeruginosa chimeric mutant strains producing lysyl-phosphatidylglycerol (L-PG) instead of the naturally occurring alanyl-phosphatidylglycerol (A-PG) to study the resulting impact on bacterial resistance. Consequences of such artificial phospholipid composition were studied in the presence of an overall of seven antimicrobials (β-lactams, a lipopeptide antibiotic, cationic antimicrobial peptides [CAMPs]) to quantitatively assess the effect of A-PG substitution (with L-PG, L-PG and A-PG, increased A-PG levels). For the employed Gram-negative P. aeruginosa model system, an exclusive charge repulsion mechanism does not explain the attenuated antimicrobial susceptibility due to PG modification. Additionally, the specificity of nine orthologous aaPGS enzymes was experimentally determined. The newly characterized protein sequences allowed for the establishment of a significant group of A-PG synthase sequences which were bioinformatically compared to the related group of L-PG synthesizing enzymes. The analysis revealed a diverse origin for the evolution of A-PG and L-PG synthases, as the specificity of an individual enzyme is not reflected in terms of a characteristic sequence motif. This finding is relevant for future development of potential aaPGS inhibitors.