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Adaptation of Pseudomonas aeruginosa to various conditions includes tRNA‐dependent formation of alanyl‐phosphatidylglycerol
Author(s) -
Klein Stefanie,
Lorenzo Carlos,
Hoffmann Sonja,
Walther Johannes M.,
Storbeck Sonja,
Piekarski Tanja,
Tindall Bryan J.,
Wray Victor,
Nimtz Manfred,
Moser Jürgen
Publication year - 2009
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2008.06562.x
Subject(s) - phosphatidylglycerol , biology , pseudomonas aeruginosa , open reading frame , escherichia coli , biochemistry , microbiology and biotechnology , mutant , heterologous , bacteria , gene , phospholipid , peptide sequence , phosphatidylcholine , membrane , genetics
Summary The opportunistic bacterium Pseudomonas aeruginosa synthesizes significant amounts of an additional phospholipid, identified as 2′ alanyl‐phosphatidylglycerol (A‐PG), when exposed to acidic growth conditions. At pH 5.3 A‐PG contributed up to 6% to the overall lipid content of the bacterium. Sequence analysis of P. aeruginosa revealed open reading frame PA0920 showing 34% sequence identity to a protein from Staphylococcus aureus involved in tRNA‐dependent formation of lysyl‐phosphatidylglycerol. The P. aeruginosa deletion mutant ΔPA0920 failed to synthesize A‐PG. Heterologous overproduction of PA0920 in Escherichia coli resulted in the formation of significant amounts of A‐PG, otherwise not synthesized by E. coli . Consequently, the protein encoded by PA0920 was named A‐PG synthase. The enzyme was identified as an integral component of the inner membrane. The protein was partially purified by detergent solubilization and subjected to an in vitro activity assay. tRNA Ala ‐dependent catalysis was demonstrated. Transcriptional analysis of the corresponding gene in P. aeruginosa using lacZ reporter gene fusion under various pH conditions indicated a 4.4‐fold acid‐activated transcription. A phenotype microarray analysis was used to identify further conditions for A‐PG function.