Incorporation of extracellular fatty acids by a fatty acid kinase-dependent pathway in Staphylococcus aureus

Mol Microbiol. 2014 Apr;92(2):234-45. doi: 10.1111/mmi.12556. Epub 2014 Mar 11.

Abstract

Acyl-CoA and acyl-acyl carrier protein (ACP) synthetases activate exogenous fatty acids for incorporation into phospholipids in Gram-negative bacteria. However, Gram-positive bacteria utilize an acyltransferase pathway for the biogenesis of phosphatidic acid that begins with the acylation of sn-glycerol-3-phosphate by PlsY using an acyl-phosphate (acyl-PO4 ) intermediate. PlsX generates acyl-PO4 from the acyl-ACP end-products of fatty acid synthesis. The plsX gene of Staphylococcus aureus was inactivated and the resulting strain was both a fatty acid auxotroph and required de novo fatty acid synthesis for growth. Exogenous fatty acids were only incorporated into the 1-position and endogenous acyl groups were channeled into the 2-position of the phospholipids in strain PDJ39 (ΔplsX). Extracellular fatty acids were not elongated. Removal of the exogenous fatty acid supplement led to the rapid accumulation of intracellular acyl-ACP and the abrupt cessation of fatty acid synthesis. Extracts from the ΔplsX strain exhibited an ATP-dependent fatty acid kinase activity, and the acyl-PO4 was converted to acyl-ACP when purified PlsX is added. These data reveal the existence of a novel fatty acid kinase pathway for the incorporation of exogenous fatty acids into S. aureus phospholipids.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Fatty Acids / metabolism*
  • Gene Knockout Techniques
  • Metabolic Networks and Pathways*
  • Phosphotransferases / genetics
  • Phosphotransferases / metabolism*
  • Staphylococcus aureus / enzymology*
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / growth & development
  • Staphylococcus aureus / metabolism*

Substances

  • Bacterial Proteins
  • Fatty Acids
  • plsX protein, bacteria
  • Phosphotransferases