Identification of a 2, 3-diamino-2, 3-dideoxyhexose in the lipid A component of lipopolysaccharides of Rhodopseudomonas viridis and Rhodopseudomonas palustris.

A hitherto unknown amino sugar (Compound A), detected in acid hydrolyzates of lipopolysaccharides of Rhodopseudomonas viridis and Rhodopseudomonas palustris, is present in the Lipid A component but not in the O-specific part of the lipopolysaccharides. 2-Amino-2-deoxy-D-glucose is lacking in the purified Lipid A of both strains. Compound A, characterized by a very high migration in paper electrophoresis was obtained in a pure state by ion-exchange chromatography and shown by m.s. of the alditol acetate to be a 2, 3-diamino-2, 3-dideoxyhexose. G.l.c. and periodate oxidation excluded all possible stereoisomers with the exception of 2, 3-diamino-2, 3-dideoxyglucose and 2, 3-diamino-2, 3-dideoxydose. G.l.c. of the alditol acetates of Compound A and of the glucose derivative suggests that Compound A is 2, 3-diamino-2, 3-dideoxyglucose. The significance of the occurrence of this new aminodeoxy sugar in the Lipid A component of Rhodopseudomonas viridis and Rhodopseudomonas palustris O-antigens for the biological properties of the respective lipopolysaccharides and for the taxonomy of the Rhodospirillaceae family is discussed.