THE STRUCTURE OF THE CORE POLYOL OF THE ETHER LIPIDS FROM SULFOLOBUS-ACIDOCALDARIUS

The major ether-type lipid structures of Sulfolobus acidocaldarius (AT CC33909) were composed of caldarchaeol and calditoglycerocaldarchaeol. However, the characterization by nuclear magnetic resonance spectrosc opy and mass spectrometry showed that the structure of calditol in cal ditoglycerocaldarchaeol is not nonitol, 3'-trihydroxypropyl)1,2,3,4,5, 6-hexahydroxyhexane, but -(2,3-dihydroxypropoxy)2,3,4,5-cyclopentanete traol with an ether linkage in the molecule. Such an intermolecular et her linkage was resistant to BCl3 treatment, but nonresistant to 57% H l degradation treatment conducted at 100 degrees C for 60 h, producing 2-hydroxymethyl-1,2,3,4,5-cyclopentanepentaol from calditol as reacti on product. Further, it was confirmed that the structure of calditol i s essentially a derivative of glycerol, and hydrocarbon chains were co njugated to the glycerol-like site in the structure. The calditol with an ether linkage in the molecule suggested an important role regardin g the properties of heat-resistance and acid-resistance observed in Su lfolobales.