Adaptation of Pseudomonas aeruginosa to various conditions includes tRNA-dependent formation of alanyl-phosphatidylglycerol.
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 DeltaPA0920 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.
Klein
Stefanie
S
Institute of Microbiology, Technische Universität Braunschweig, Spielmannstrasse 7, Braunschweig, Germany.
Lorenzo
Carlos
C
Hoffmann
Sonja
S
Walther
Johannes M
JM
Storbeck
Sonja
S
Piekarski
Tanja
T
Tindall
Bryan J
BJ
Wray
Victor
V
Nimtz
Manfred
M
Moser
Jürgen
J
D000222:Adaptation, Physiological; D019881:Aminoacyltransferases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D016366:Open Reading Frames; D010641:Phenotype; D010715:Phosphatidylglycerols / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics; D012344:RNA, Transfer, Ala / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D010715:Phosphatidylglycerols; D012344:RNA, Transfer, Ala; D011993:Recombinant Fusion Proteins; C015656:alanylphosphatidylglycerol; D019881:Aminoacyltransferases; C562342:alanyl-phosphatidylglycerol synthase, Pseudomonas aeruginosa