Total synthesis of geranylgeranylglyceryl phosphate enantiomers: substrates for characterization of 2,3-O-digeranylgeranylglyceryl phosphate synthase.

To determine the enantioselectivity of (S)-2,3-di-O-geranylgeranylglyceryl phosphate synthase (DGGGPS) from the thermoacidophilic archaeon Sulfolobus solfataricus, we developed an efficient enantioselective route to the enantiomeric geranylgeranylglyceryl phosphates (R)-GGGP and (S)-GGGP. Previous routes to these substrates involved enzymatic conversions due to the lability of the polyprenyl chains toward common phosphorylation reaction conditions. The synthesis described herein employs a mild trimethyl phosphite/carbon tetrabromide oxidative phosphorylation to circumvent this problem. In contrast to previous results suggesting that only (S)-GGGP can act as the prenyl acceptor substrate, both (R)-GGGP and (S)-GGGP were found to be substrates for DGGGPS.