Phospholipids of a moderately halophilic halotolerant bacterium. Isolation and identification of glucosylphosphatidyl-glycerol

1. 1. The composition of the polar lipids of a Gram-negative, moderately halophilic halotolerant bacterium was determined. The following lipids (in decreasing amounts) were found: phosphatidylethanolamine, phosphatidylglycerol, a glucuronic acid containing glycolipid, α-glucosylphosphatidylglycerol and cardiolipin. 2. 2. The elucidation of the structure of glucosylphosphatidylglycerol is based on the following observations: (a) Degradation by phospholipase C yielded diglycerides and a water-soluble product which upon add hydrolysis yielded glucose and glycerol phosphate, (b) Hydrolysis with 60% HF yielded diglycerides, inorganic phosphate, glucosylglycerol and small amounts of the water-soluble product which was obtained by phospholipase C. (c) Glucosylglycerol was hydrolyzed by α-glucosidase. 3. 3. The fatty acids of these lipids had an unusually high content of 11,12-methylene octadecanoic acid which was preferentially located at carbon 2 of the phosphatidyl unit.