Studies on chloroplast membranes. III. 13C chemical shifts and longitudinal relaxation times of 1,2-Diacyl-3-(6-sulpho-α-quinovosyl)-sn-glycerol

Abstract

13C Chemical shifts, longitudinal relaxation times and some nuclear Overhauser enhancement factors of the individual carbon atoms in the chloroplast lipid, 1,2-diacyl-3-(6-sulpho-α-quinovosyl)-sn-glycerol (sl), have been measured in the three solvents: methanol[D4], chloroform[D] and water[D2]. Correlation times for the individual carbon atoms calculated from these results have been interpreted in terms of different secondary structures: a monomeric structure in methanol[D4], an inverted micellar structure in chloroform[D] and a bilayer vesicular structure in water[D2]. Substituent shift parameters have been determined for the sulphonic acid group from a series of alkanesulphonic acids and these have been used in the 13C chemical shift assignments in sl and a series of model compounds.