Two unusual glycerophospholipids from a filamentous fungus, Absidia corymbifera

• Published in: Biochimica et biophysica acta 2001-04, Vol.1531 (3), p.169-177
• Main Authors: Batrakov, Stanislav G, Konova, Inessa V, Sheichenko, Vladimir I, Esipov, Stanislav E, Galanina, Lyudmila A
• Format: Article
• Language: English
• Subjects: Absidia - chemistry; Absidia - genetics; Absidia corymbifera; Fatty Acids - analysis; Glycerophospholipids - chemistry; Glycerophospholipids - isolation & purification; Magnetic Resonance Spectroscopy; Molecular Structure; N-Acetyl phosphatidylethanolamine; N-Ethoxycarbonyl phosphatidylethanolamine; Phosphatidylethanolamines - chemistry; Phospholipid; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Spectrophotometry, Infrared
• ISSN: 1388-1981; 0006-3002; 1879-2618
• DOI: 10.1016/S1388-1981(01)00082-8

The chloroform–methanol extractable lipids of the soil filamentous fungus Absidia corymbifera VKMF-965 account for about 20% by weight of dry cells and are composed of low-polarity constituents (about 75% of the total lipids), such as triacylglycerols (mainly), diacylglycerols, sterols and free fatty acids, as well as of glycolipids (about 3%) and phospholipids. The last consist largely of components common to the fungal lipids, namely, phosphatidylethanolamine (38% of the total phospholipids), phosphatidyl- myo-inositol (16%), diphosphatidylglycerol (12%), phosphatidylcholine (7%), phosphatidic acid (6%) and phosphatidylglycerol (3%), and two unusual phospholipids, PL1 (6%) and PL2 (9%). Based on the infrared (IR), 1H-nuclear magnetic resonance (NMR), 13C-NMR and mass spectra along with the results of degradation experiment, these two phospholipids have been established to be 1,2-diacyl- sn-glycero-3-phospho( N-acetylethanolamine), or N-acetyl phosphatidylethanolamine, and 1,2-diacyl- sn-glycero-3-phospho( N-ethoxycarbonyl-ethanolamine), respectively. These structures have been confirmed by preparing similar phospholipids from the phosphatidylethanolamine isolated from the same fungus and correlating their chromatographic behaviour, IR and 1H-NMR spectra with those of PL1 and PL2. So far N-acetyl phosphatidylethanolamine has been detected only in cattle and human brains and a human placenta but its structure was not rigorously proved. PL2 is a novel lipid; to our knowledge no natural phospholipid with an urethane group has yet been found. The main fatty acids of both the phospholipids are n-hexadecanoic, octadecanoic and octadecadienoic ones; PL2 contains in addition a considerable amount of octadecatrienoic acid with its greater portion located at the sn-1 position.