Phospholipid composition of several clinically relevant Corynebacterium species as determined by mass spectrometry: an unusual fatty acyl moiety is present in inositol-containing phospholipids of Corynebacterium urealyticum

Abstract

A comparative study on phospholipids ofCorynebacterium amycolatum,Corynebacterium jeikeiumandCorynebacterium urealyticumwas carried out using fast-atom bombardment (FAB) and electrospray ionization (ESI) mass spectrometry. Data obtained indicate the presence of acylphosphatidylglycerol (APG), diphosphatidylglycerol, phosphatidylglycerol (PG), phosphatidylinositol (PI) and triacylphosphatidylinositol dimannosides (Ac3PIM2) in these bacteria. In general, octadecenoyl and hexadecanoyl fatty acyl moieties predominated in phospholipids ofC. amycolatum, whereas high levels of hexadecenoyl were found inC. jeikeiumandC. urealyticum. Mass spectra from purified APG and PG indicated that thesn-1 position of the glycerol was occupied by octadecenoyl in the three species studied. Notably, several major molecular species of PI and Ac3PIM2fromC. urealyticumcontained significant amounts of a moiety identified as 10-methyleneoctadecanoyl, located at thesn-1 position of these molecules. On the other hand, multiantibiotic resistant and susceptible strains ofC. amycolatumdiffered in several minor phospholipid fatty acids of 19 carbon atoms, identified as 10-methyloctadecenoic, 10-methyloctadecanoic (tuberculostearic acid) and 10-methyleneoctadecanoic. The results demonstrate an overall similarity among the phospholipids of the different species studied but also significant differences related to the acyl chains of the glycerol moiety of these compounds, notably the high levels of an unusual fatty acyl moiety in inositol-containing phospholipids ofC. urealyticum.