The Acylation State of Surface Lipoproteins of Mollicute Acholeplasma laidlawii

• Published in: The Journal of biological chemistry Vol. 286; no. 26; pp. 22769 - 22776
• Main Authors: Serebryakova, Marina V., Demina, Irina A., Galyamina, Maria A., Kondratov, Ilya G., Ladygina, Valentina G., Govorun, Vadim M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2011; American Society for Biochemistry and Molecular Biology
• Subjects: 2D PAGE; Acetylation; Acholeplasma laidlawii - chemistry; Acholeplasma laidlawii - genetics; Acholeplasma laidlawii - metabolism; Acyltransferases - chemistry; Acyltransferases - genetics; Acyltransferases - metabolism; Bacteria; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Fatty Acid; Lipoprotein; Lipoproteins - chemistry; Lipoproteins - genetics; Lipoproteins - metabolism; Mass Spectrometry (MS); Membrane Biology; Membrane Proteins; Protein Processing, Post-Translational - physiology; Membrane Proteins; Mass Spectrometry (MS); Bacteria; Lipoprotein; 2D PAGE; Fatty Acid
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M111.231316

Acylation of the N-terminal Cys residue is an essential, ubiquitous, and uniquely bacterial posttranslational modification that allows anchoring of proteins to the lipid membrane. In Gram-negative bacteria, acylation proceeds through three sequential steps requiring lipoprotein diacylglyceryltransferase, lipoprotein signal peptidase, and finally lipoprotein N-acyltransferase. The apparent lack of genes coding for recognizable homologs of lipoprotein N-acyltransferase in Gram-positive bacteria and Mollicutes suggests that the final step of the protein acylation process may be absent in these organisms. In this work, we monitored the acylation state of eight major lipoproteins of the mollicute Acholeplasma laidlawii using a combination of standard two-dimensional gel electrophoresis protein separation, blotting to nitrocellulose membranes, and MALDI-MS identification of modified N-terminal tryptic peptides. We show that for each A. laidlawii lipoprotein studied a third fatty acid in an amide linkage on the N-terminal Cys residue is present, whereas diacylated species were not detected. The result thus proves that A. laidlawii encodes a lipoprotein N-acyltransferase activity. We hypothesize that N-acyltransferases encoded by genes non-homologous to N-acyltransferases of Gram-negative bacteria are also present in other mollicutes and Gram-positive bacteria.