Genetic regulation of fatty acid modifying enzyme from Staphylococcus aureus

Fatty acid modifying enzyme (FAME) is an extracellular enzyme that inactivates staphylocidal lipids by catalysing the esterification of these lipids to cholesterol. In-vitro expression of FAME began at the start of the stationary phase. This expression of FAME was very similar to other staphylococcal extracellular proteins controlled by the global regulators Agr and Sar. A Staphylococcus aureus strain ISP546 (Agr(-)) produced c. 80% less FAME than an isogenic Agr(+) strain ISP479C. Similar results were obtained with the isogenic Agr(+)/Agr(-) strain pair RN6390 and RN6911. A S. aureus strain R (Sar(-)) produced c. 86% less FAME than an isogenic Sari strain RN6390. However, lipase assays on the same culture filtrates from the Sar(+)/Sar(-) strains did not demonstrate any affect on lipase production by the sar mutation.