Discovery of a bifunctional cardiolipin/phosphatidylethanolamine synthase in bacteria. Issue 5 (29th April 2014)

• Record Type: Journal Article
• Authors: Moser, Roman; Aktas, Meriyem; Fritz, Christiane; Narberhaus, Franz
• Is Part Of: Molecular microbiology. Volume 92:Issue 5(2014)
• Page Start: 959
• Page End: 972
• Publication Date: 2014-04-29
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12603
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>Phosphatidylethanolamine (PE) and cardiolipin (CL) are major components of bacterial and eukaryotic membranes. In bacteria, synthesis of PE usually occurs via decarboxylation of phosphatidylserine (PS) by PS decarboxylases (Psd). CL is produced by various CL synthases (Cls). Membranes of the plant pathogen <italic>X</italic><italic>anthomonas campestris</italic> predominantly contain PE, phosphatidylglycerol (PG) and CL. The <italic>X</italic><italic>. campestris</italic> genome encodes one Psd and six putative CLs. Deletion of <italic>psd</italic> resulted in loss of PE and accumulation of PS. The mutant was severely affected in growth and cell size. PE synthesis, growth and cell division were partially restored when cells were supplied with ethanolamine (EA) suggesting a previously unknown PE synthase activity. Via mutagenesis, we identified a Cls enzyme (Xc_0186) responsible for EA‐dependent PE biosynthesis. <italic>X</italic><italic>anthomonas</italic> lacking <italic>xc_0186</italic> not only lost its ability to utilize EA for PE synthesis but also produced less CL suggesting a bifunctional enzyme. Recombinant Xc_0186 in <italic>E</italic><italic>. coli</italic> and in cell‐free extracts uses cytidine diphosphate diacylglycerol (CDP‐DAG) and PG for CL synthesis. It is also able to use CDP‐DAG and EA for PE synthesis. Owing to its dual function in CL and PE production, we consider Xc_0186 the founding member of a new class of enzymes called CL/PE synthase (CL/PEs).</p> </abstract>