Trna-Dependent Alanylation Of Diacylglycerol And Phosphatidylglycerol In Corynebacterium Glutamicum

Abstract

Aminoacyl-phosphatidylglycerol synthases (aaPGSs) are membrane proteins that utilize aminoacylated tRNAs to modify membrane lipids with amino acids. Aminoacylation of membrane lipids alters the biochemical properties of the cytoplasmic membrane and enables bacteria to adapt to changes in environmental conditions. aaPGSs utilize alanine, lysine and arginine as modifying amino acids, and the primary lipid recipients have heretofore been defined as phosphatidylglycerol (PG) and cardiolipin. Here we identify a new pathway for lipid aminoacylation, conserved in many Actinobacteria, which results in formation of Ala-PG and a novel alanylated lipid, Alanyl-diacylglycerol (Ala-DAG). Ala-DAG formation in Corynebacterium glutamicum is dependent on the activity of an aaPGS homolog, whereas formation of Ala-PG requires the same enzyme acting in concert with a putative esterase encoded upstream. The presence of alanylated lipids is sufficient to enhance the bacterial fitness of C.glutamicum cultured in the presence of certain antimicrobial agents, and elucidation of this system expands the known repertoire of membrane lipids acting as substrates for amino acid modification in bacterial cells. In this study, we revealed a new aa-tRNA-dependent pathway for lipid aminoacylation in Corynebacterium glutamicum, which is conserved in various Actinobacteria. This pathway produces alanyl-diacylglycerol (Ala-DAG) in addition to alanyl-phosphatidylglycerol (Ala-PG). While Ala-DAG is synthesized by a homolog (Ala-DAGS) of the gene MprF, synthesis of Ala-PG is dependent on the presence of a putative esterase (PesT). We showed that this pathway enhances the fitness of C. glutamicum when challenged by certain antimicrobial compounds. AlaRS: Alanyl-tRNA synthetase.

Publication Date

11-1-2015

Publication Title

Molecular Microbiology

Volume

98

Issue

4

Number of Pages

681-693

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1111/mmi.13150

Socpus ID

84947023019 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84947023019

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