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J Biol Chem. 2016 Nov 25;291(48):25144-25153. Epub 2016 Oct 19.

In Vivo and in Vitro Synthesis of Phosphatidylglycerol by an Escherichia coli Cardiolipin Synthase.

Author information

1
From the Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710.
2
From the Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710 ziqiang.guan@duke.edu.

Abstract

Phosphatidylglycerol (PG) makes up 5-20% of the phospholipids of Escherichia coli and is essential for growth in wild-type cells. PG is synthesized from the dephosphorylation of its immediate precursor, phosphatidylglycerol phosphate (PGP) whose synthase in E. coli is PgsA. Using genetic, biochemical, and highly sensitive mass spectrometric approaches, we identified an alternative mechanism for PG synthesis in E. coli that is PgsA independent. The reaction of synthesis involves the conversion of phosphatidylethanolamine and glycerol into PG and is catalyzed by ClsB, a phospholipase D-type cardiolipin synthase. This enzymatic reaction is demonstrated herein both in vivo and in vitro as well as by using the purified ClsB protein. When the growth medium was supplemented with glycerol, the expression of E. coli ClsB significantly increased PG and cardiolipin levels, with the growth deficiency of pgsA null strain also being complemented under such conditions. Identification of this alternative mechanism for PG synthesis not only expands our knowledge of bacterial anionic phospholipid biosynthesis, but also sheds light on the biochemical functions of the cls gene redundancy in E. coli and other bacteria. Finally, the PGP-independent PG synthesis in E. coli may also have important implications for the understanding of PG biosynthesis in eukaryotes that remains incomplete.

KEYWORDS:

Escherichia coli (E. coli); Phosphatidylglycerol; cardiolipin; mass spectrometry (MS); phosphatidylethanolamine; phosphatidylglycerol

PMID:
27760827
PMCID:
PMC5122781
DOI:
10.1074/jbc.M116.762070
[Indexed for MEDLINE]
Free PMC Article

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