Lipoproteins of slow-growing Mycobacteria carry three fatty acids and are N-acylated by Apolipoprotein N-Acyltransferase BCG_2070c

BMC Microbiology

Research Article

Juliane K Brülle¹  Andreas Tschumi¹  Peter Sander² 

[1] Institute of Medical Microbiology, University of Zurich, Gloriastrasse 30/32, CH-8006, Zurich, Switzerland;Institute of Medical Microbiology, University of Zurich, Gloriastrasse 30/32, CH-8006, Zurich, Switzerland;National Reference Laboratory for Mycobacteria (NRLM), Gloriastrasse 30, CH-8006, Zurich, Switzerland;

关键词: Mycobacteria;    Tuberculosis;    Lipoprotein;    Lipidation;    N;   

DOI  :  10.1186/1471-2180-13-223

 received in 2013-07-10, accepted in 2013-09-30,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundLipoproteins are virulence factors of Mycobacterium tuberculosis. Bacterial lipoproteins are modified by the consecutive action of preprolipoprotein diacylglyceryl transferase (Lgt), prolipoprotein signal peptidase (LspA) and apolipoprotein N- acyltransferase (Lnt) leading to the formation of mature triacylated lipoproteins. Lnt homologues are found in Gram-negative and high GC-rich Gram-positive, but not in low GC-rich Gram-positive bacteria, although N-acylation is observed. In fast-growing Mycobacterium smegmatis, the molecular structure of the lipid modification of lipoproteins was resolved recently as a diacylglyceryl residue carrying ester-bound palmitic acid and ester-bound tuberculostearic acid and an additional amide-bound palmitic acid.ResultsWe exploit the vaccine strain Mycobacterium bovis BCG as model organism to investigate lipoprotein modifications in slow-growing mycobacteria. Using Escherichia coli Lnt as a query in BLASTp search, we identified BCG_2070c and BCG_2279c as putative lnt genes in M. bovis BCG. Lipoproteins LprF, LpqH, LpqL and LppX were expressed in M. bovis BCG and BCG_2070c lnt knock-out mutant and lipid modifications were analyzed at molecular level by matrix-assisted laser desorption ionization time-of-flight/time-of-flight analysis. Lipoprotein N-acylation was observed in wildtype but not in BCG_2070c mutants. Lipoprotein N- acylation with palmitoyl and tuberculostearyl residues was observed.ConclusionsLipoproteins are triacylated in slow-growing mycobacteria. BCG_2070c encodes a functional Lnt in M. bovis BCG. We identified mycobacteria-specific tuberculostearic acid as further substrate for N-acylation in slow-growing mycobacteria.

【 授权许可】

Unknown   
© Brülle et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.