Carotenoid Glycoside Esters from the Thermophilic Bacterium Meiothermus ruber

The thermophilic bacterium Meiothermus ruber produces a series of carotenoid glycoside esters. The major carotenoid has been identified as 1'-beta-glucopyranosyl-3,4,3',4'-tetradehydro-1', 2'-dihydro-beta,psi-caroten-2-one (1). It is acylated at the 6' '-position of the glucose unit by a series of C10-C17 fatty acids. The structure of 1 was established by spectral means, including complete assignment of the 1H and 13C NMR resonances by inverse 2D NMR spectroscopy. These carotenoids are thought to play roles in stabilizing membranes of this thermophilic organism.