NMR-STUDIES OF ACETAN AND THE RELATED BACTERIAL POLYSACCHARIDE, CR1 4, PRODUCED BY A MUTANT STRAIN OF ACETOBACTER-XYLINUM/

Acetan is a bacterial polysaccharide produced by Acetobacter xylinum N RRL B42. Chemical mutagenesis of A.xylinum allowed selection of a muta nt strain which produced a new polysaccharide, CR1/4. 2D NMR methods h ave been used to assign the H-1 and C-13 spectra of the two polysaccha rides and to determine that CR1/4 has the structure shown below. The t otal number of O-acetyl groups is slightly less than two per repeating unit, [GRAPHICS] The pentasaccharide side chain of acetan is truncate d to a disaccharide unit in CR1/4, but the structures are otherwise id entical. In particular, the degree of acetylation is about the same an d the O-acetyl groups are located at the same positions in both polysa ccharides.