Bis(monoacylglycero)phosphate in alkalophilic bacteria.

Abstract

Bis(monoacylglycero)phosphate (BMP) was found in an alkalophilic bacterium, Bacillus sp. A-007. This lipid comprised 4% of the phospholipid of this organism. The very low rate and extent of triphenylmethylation of BMP indicated that the two fatty acid residues occupied the C-1 and C-3' positions of the two glycerol moieties. The stereochemical configuration of the backbone of BMP was identified as sn-glycero-3-phosphoryl-1'-sn-glycerol by sn-glycerol 3-phosphate dehydrogenase analysis after acetic acid hydrolysis and mild alkaline methanolysis. This configuration was the same as that of phosphatidylglycerol, but differed from that of BMP from mammalian cells. Finally, the structure of BMP in Bacillus sp. A-007 was concluded to be 1-acyl-sn-glycero-3-phosphoryl-1' (3'-acyl)-sn-glycerol. The fatty acids of BMP were those common in Bacillus species. The fatty acid composition of BMP was very similar to that of the major lipids in this organism. The fatty acid distribution between the C-1 and C-3' positions of BMP was determined by a newly developed method which included successive steps of acetic acid hydrolysis, chemical acylation and phospholipase A2 treatment. Fatty acids with longer chain length were concentrated in the C-1 position, and the shorter fatty acids were the major ones esterified at the C-3' position.