Colominic acid

Three 3-deoxynonulosonic acids containing amino groups are known. The most abundant of these is 5-amino-3,5-deoxy-D- /yc ro-D-ga/acto-nonulosonic acid (neuraminic acid, 27), which occurs in different extracellular polysaccharides. Some of these, like colominic acid from E. coli K1, are homopolysaccharides. Neuraminic acid is generally A-acetylated and, as in the animal glycoconjugates, has only been found in the a-pyranosyl form (27). It also occurs in some LPS, for example those from some Rhodobacter... 

Colominic acid, classification by structure, 4 723t Colon... 

Acetylation at 0-9 seems to be a phylogenetically old acquisition, as Neu9Ac5Gc occurs in the sea-urchin species Pseudocentrotus de-pressus (Okayama).62 Acetyl groups at 0-9 of Neu have, with the aid of I3C-n.m.r. spectroscopy,77 also been found in E. coli K-l colominic acid. 

The occurrence of%-O-acetylated sialic acid in colominic acid has also been reported.47 Although the substance has not yet been obtained in pure form, there is some evidence for the existence of... 

R. Roy and R. A. Pon, Efficient synthesis of a(2->8)-linked W-acetyl and N-glycolylneuraminic acid disaccharides from colominic acid, Glycoconjugate J. 7 3 (1990). 

Colominic acid (E. colt polyNeuNAc), sialic acids, mucoproteins, glycolipids... 

Not all capsular polysaccharides of uropathogenic and invasive coli bacteria contain KDO. Some of the non-KDO capsular polysaccharides are shown in Figure 12 (11-16). These are the Kl, K2, K5 and K51 polysaccharides. The Kl polysaccharide is a poly-a-2.8-N-acetyl-neuraminic acid and has been known as colominic acid since many years (11). Its structure which is identical with that of the capsular antigen of Neisseria meningitidis B has first been reported by McGuire and Binkley... 

A preparation of colominic acid [poly-(V-acetylneuraminic acid)] prepared from a culture filtrate of a certain strain of Escherichia coli could be fractionated by ion-exchange chromatography into several fractions containing ultraviolet-absorbing material. One fraction contained uridine pjTophosphate linked to a neuraminic peptide. It is suggested that the... 

A substance later shown to be muramic acid (see Section IV,6) was clearly different from the product of Vi antigen, and, although the strain used in some of the Vi studies (Escherichia coli 5396/38) is one in which sialic acid has been detected, the properties of the Vi antigen are markedly different from the neuraminic acid pol3oner. Infrared spectra recorded for crystalline V-acetyl-neuraminic acid exhibit full detail and cannot be compared with that published for aminohexuronic acid, but that of the amorphous neuraminic acid polymer (colominic acid) is rather similar to that of the Vi antigen polymeric unit, since their functional groups are very similar. The relationship of these substances to the property of 0 -inagglutinability is discussed later (see p. 336). 

When the fraction soluble in 90 %-saturated ammonium sulfate (the fraction containing colominic acid) was recovered by dialysis instead of by precipitation, some very interesting products, having lower molecular weight and containing neuraminic acid, were found. It was confirmed that colominic acid contained V-acetyl-neuraminic acid to the extent of at least 80 %. 

Cinnamic acid, 268 Cobalamin, 236 Colititol, 285 Colitose, 284, 311 Colominic acid, 233, 296, 336,337 Conformational analysis, 11,12 Conformations, during anomerization, 42... 

However, in the a-(268) linked sialic acid oligomers, the OH-8 is replaced by OR-8, where R is the bulky quaternary center C-2 of the next sialic acid. Not surprisingly, in the a-(268) linked sialic acid trisaccharide and in the a-(268) linked sialic acid polymer, colominic acid, mixtures of rotamers about the C-7-C-8 bond are adopted [219,220] that have been interpreted for the polymer as giving a helix [221] or a short-lived helix [219], consistent with this polymer being a conformational epitope for serogroup B of Neisseria meningitidis. More recent detailed NMR relaxation studies have concluded that the polymer is a random coil with no helix present for any extended period and that the polymer has considerable flexibility about the exocyclic torsional angles [222]. 

Conformational structures of segments of sodium alginate, containing /3-D-mannopyranosyl uronic acid, and ol-L-gulopyranosyl uronic acid and 2,8-o -colominic acid, containing / f-acetyl-o -D-neuraminic acid, linked (2- 8)... 

The second family of A-linked oligosaccharides are called the lactosamine family in which the D-mannose residues of the core pentasaccharide are substituted 1 2 by lactosamine, which is a lactose analogue with A-acetyl-D-glucosamine substituted for D-glucopyranose at the reducing-end of lactose. The lactosamine is frequently substituted by A-acetyl-D-neu-raminic acid (for the structure of A-acetyl-D-neuraminic acid, see the monomer residue in colominic acid,0 Sect. 8.2 andO Fig. 7) linked 2 3 or 2 6 [142,143]. The third family has a mixed structure of the high mannose and lactosamine families [144,145,146,147]. 

The distribution of the acids does not appear to be confined solely to the animal kingdom, for Barry and GoebeP have reported the isolation of colominic acid, a polymerized form of iV-acetylneuraminic acid, from culture filtrates of Escherichia coli. It remains to be established whether other bacteria and microorganisms possess the capacity to synthesize and utilize these acids. 

The finding of colominic acid, produced by phage-resistant Escherichia coli, prompts speculation as to whether or not this phage-resistance is, in... 

Chromatography, ion-exchange, 250, 251 Clostridium perfringens, 262 Colominic acid, 242, 261 Colostrum, 240, 245, 251, 258 Complex compounds, of celluloses, 296 of formazans with metals, 108 Condensation, aldol, 77 Crotonic acid, 177, 180... 

---