STRUCTURE OF THE O-SPECIFIC POLYSACCHARIDE OF THE BACTERIUM PROTEUS-MIRABILIS O-10 CONTAINING L-ALTRURONIC ACID, A NEW COMPONENT OF O-ANTIGENS

An acidic O-specific polysaccharide was obtained by mild acid degradat ion of the lipopolysaccharide of the bacterium Proteus mirabilis O10 a nd studied by full acid hydrolysis, carboxyl reduction, and H-1- and C -13-NMR spectroscopy, including two-dimensional correlation spectrosco py (COSY4), H-detected heteronuclear H-1, C-13 multi-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (RO ESY). It was found that the polysaccharide contains 2-acetamido-2-deox y-D-glucose, 2-acetamido-2-deoxy-D-galactose, D-galacturonic acid, and L-altruronic acid, and the following structure of the branched tetras accharide repealing unit of the polysaccharide was established: [GRAPH ICS] t azide-facilitated decay of the M intermediate and shift the lin ear part of the dose-response curve of the effect of the azide concent ration on the intermediate M decay rate to higher azide concentrations . The efficiency of azide as an accelerator of the M intermediate deca y in these two populations decreases 11- and 140-fold in the presence of glutaraldehyde and 200- and 1600-fold in the presence of LuCl3. Gly cerol and sucrose induce deceleration of the M intermediate decay in t he wild-type bacteriorhodopsin and in the D96N mutant in the presence of azide, A scheme for the photocycle is suggested that assumes an equ ilibrium of two M intermediate forms differing in permeability for azi de and, probably, for water molecules.