Sulfoquinovosylglyceryl ether, a new group of ether lipids from lake ball-forming green alga Aegagropilopsis moravica (family Pithophoraceae).

Ether lipids are a minor group of glycerolipids but widespread in nature, playing a vital function as membrane lipids, signalling molecules, or buoyant material. We have discovered sulfoquinovosylchimyl alcohol (1), a sulfonate-substituted glyceroglycolipid, from a lake ball-forming green alga Aegagropilopsis moravica (family Pithophoraceae), with the guidance of antimicrobial activity. The structure of 1, including absolute configurations of all sterogenic centers, was established by extensive NMR analysis, chemical degradation studies, and finally by total synthesis. Lipid 1 is an ether variant of a lyso-form of sulfoquinovosyldiacylglycerol, a chloroplast-specific membrane lipid, and thus represents a new lipid class, sulfoquinovosylglyceryl ether. A high occurrence of mobile life form in the family Pithophoraceae and a unique behaviour of chloroplasts reported in closely related Aegagropila linnaei, the famous lake-ball alga, implies a possible role of lipid 1 or its acyl derivatives in ecological adaptation to dysphotic niches.