An exceptionally large repeating unit has been proposed for one of the two O-specific polysaccharides of the lipopolysaccharide from Pseudomonas (Burkholderia) caryophylli, which is a homopolymer of the sugar caryose. This proposal is based on the unusual acetylation pattern of the carbohydrate (shown in the picture), as determined from the presence of eight independent spin systems observed by NMR spectroscopy. A=acetylated, D=non-acetylated caryose monomer.