PRIMARY STRUCTURE OF A NEW PHOSPHOCHOLINE-CONTAINING GLYCOGLYCEROLIPID OF MYCOPLASMA-FERMENTANS

The chemical structure of a novel phosphocholine-containing glycoglyce rolipid, the major polar lipid in the cell membrane of Mycoplasma ferm entans PG18, was investigated by chemical analyses, gas-liquid chromat ography-mass spectrometry, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, as well as one-and two- dimensional homo-and heteronuclear NMR spectroscopy and identified as 6'-O-(3 ''-phosphocholine-2 ''-amino-1 ''-phospho- 1 '',3 lpha-D-gluco pyranosyl-(1'-->3)-1,2-diacyl-glycerol (MfGL-II), Palmitate (16:0) and stearate (18:0), in a 3.6:1 molar ratio, constitute the major fatty a cids present, MALDI-TOF mass spectrometry revealed two major pseudomol ecular ions at m/z 1049.5 [M-I + H](+) and 1077.3 [M-II + H](+) repres enting a dipalmitoyl as the major component and a palmitoyl-stearoyl s tructure as a minor component. This is the first report of 2-amino-1,3 -propanediol-1,3-bisphosphate present in a natural product, This glyco glycerolipid is the second phosphocholine-containing glycoglycerolipid found in M. fermentans.