Isolation using triflic acid solvolysis and identification of N(epsilon)-[(R)-1-carboxyethyl]-N(alpha)-(D-galacturonoyl)-L-lysine as a component of the O-specific polysaccharide of Proteus mirabilis O13

Structure and serology of O-antigens as the basis for classification of Proteus strains

This review is devoted to structural and serological characteristics of the O-antigens (O-polysaccharides) of the lipopolysaccharides of various Proteus species, which provide the basis for classifying Proteus strains to Oserogroups. The antigenic relationships of Proteus strains within and beyond the genus as well as their O-antigenrelated bioactivities are also discussed.

Molecular structure of endotoxins from Gram-negative marine bacteria: an update

Marine bacteria are microrganisms that have adapted, through millions of years, to survival in environments often characterized by one or more extreme physical or chemical parameters, namely pressure, temperature and salinity. The main interest in the research on marine bacteria is due to their ability to produce several biologically active molecules, such as antibiotics, toxins and antitoxins, antitumor and antimicrobial agents. Nonetheless, lipopolysaccharides (LPSs), or their portions, from Gram-negative marine bacteria, have often shown low virulence, and represent potential candidates in the development of drugs to prevent septic shock. Besides, the molecular architecture of such molecules is related to the possibility of thriving in marine habitats, shielding the cell from the disrupting action of natural stress factors. Over the last few years, the depiction of a variety of structures of lipids A, core oligosaccharides and O-specific polysaccharides from LPSs of marine microrganisms has been given. In particular, here we will examine the most recently encountered structures for bacteria belonging to the genera Shewanella, Pseudoalteromonas and Alteromonas, of the gamma-Proteobacteria phylum, and to the genera Flavobacterium, Cellulophaga, Arenibacter and Chryseobacterium, of the Cytophaga-Flavobacterium-Bacteroides phylum. Particular attention will be paid to the chemical features expressed by these structures (characteristic monosaccharides, non-glycidic appendages, phosphate groups), to the typifying traits of LPSs from marine bacteria and to the possible correlation existing between such features and the adaptation, over years, of bacteria to marine environments.

Structure of an acidic O-specific polysaccharide from marine bacterium Shewanella fidelis KMM 3582T containing Nε-[(S)-1-carboxyethyl]-Nα-(d-galacturonoyl)-l-lysine

The O-specific polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of the marine bacterium Shewanella fidelis type strain KMM 3582T and studied by sugar analysis along with 1H and 13C NMR spectroscopy including one-dimensional NOE in difference mode and two-dimensional experiments. The polysaccharide was found to consist of linear tetrasaccharide repeating units containing Nepsilon-[(S)-1-carboxyethyl]-Nalpha-(D-galacturonoyl)-L-lysine and having the following structure: [See text.] The amide of D-galacturonic acid with Nepsilon-[(S)-1-carboxyethyl]-L-lysine ('alaninolysine', 2S,8S-AlaLys) was found for the first time in nature as a component of the O-specific polysaccharide of Providencia rustigianii O14 (Carbohydr. Res. 2003, 338, 1009-1016).

Structure of the O-polysaccharide from Proteus myxofaciens. Classification of the bacterium into a new Proteus-O-serogroup

The O-polysaccharide (O-antigen) was obtained from the lipopolysaccharide of Proteus myxofaciens, a Proteus strain producing copious amounts of slime, which was isolated from the gypsy moth larvae. The structure of the polysaccharide was studied by chemical analysis and 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, ROESY and H-detected 1H,13C HMQC experiments. It was found that the polysaccharide contains an amide of glucuronic acid (GlcA) with an unusual alpha-linked amino acid, Nepsilon-[(R)-1-carboxyethyl]-l-lysine (2S,8R-alaninolysine, 2S,8R-AlaLys), and has a linear tetrasaccharide repeating unit of the following structure: This structure is unique among known bacterial polysaccharide structures. On the basis of these and serological data, it is proposed that P. myxofaciens be classified into a new Proteus serogroup, O60, of which this strain is the single representative. Structural and serological relatedness of P. myxofaciens to other AlaLys-containing O-antigens of Proteus and Providencia is discussed.

Structure of the O-specific polysaccharide of Providencia rustigianii O14 containing N(epsilon)-[(S)-1-carboxyethyl]-N(alpha)-(D-galacturonoyl)-L-lysine

The O-specific polysaccharide of Providencia rustigianii O14 was obtained by mild acid degradation of the LPS and studied by chemical methods and NMR spectroscopy, including 2D 1H,(1)H COSY, TOCSY, NOESY, and 1H,(13)C HSQC experiments. The polysaccharide was found to contain N (epsilon)-[(S)-1-carboxyethyl]-N(alpha)-(D-galacturonoyl)-L-lysine ('alaninolysine', 2S,8S-AlaLys). The amino acid component was isolated by acid hydrolysis and identified by 13C NMR spectroscopy and specific optical rotation, using synthetic diastereomers for comparison. The following structure of the trisaccharide repeating unit of the polysaccharide was established:Anti-P. rustigianii O14 serum was found to cross-react with O-specific polysaccharides of Providencia and Proteus strains that contains amides of uronic acid with N(epsilon)-[(R)-1-carboxyethyl]-L-lysine and L-lysine.

Structure of the O-specific polysaccharide of Proteus vulgaris O4 containing a new component of bacterial polysaccharides, 4,6-dideoxy-4

A high-molecular-mass O-specific polysaccharide was obtained by mild acid degradation of Proteus vulgaris O4 lipopolysaccharide followed by GPC. The polysaccharide was studied by chemical methods along with 1H and 13C NMR spectroscopy, including two-dimensional COSY, TOCSY, NOESY, H-detected 1H,13C HMQC, and 1H,13C HMBC experiments. Solvolysis of the polysaccharide with trifluoromethanesulfonic (triflic) acid resulted in a GlcpA-(1 --> 3)-GlcNAc disaccharide and a novel amino sugar derivative, 4,6-dideoxy-4-[N-[(R)-3-hydroxybutyryl]-L-alanyl]amino-D-glucose [Qui4N(HbAla)]. On the basis of the data obtained, the following structure of the tetrasaccharide repeating unit of the O-specific polysaccharide was established: --> 4)-beta-D-GlcpA-(1 --> 3)-beta-D-GlcpNAc-(1 --> 2)-beta-D-Quip4N(HbAla)-(1 --> 3)-alpha-D-Galp-(1 -->. This structure is unique among the O-specific polysaccharides, which is in accordance with classification of the strain studied in a separate Proteus serogroup.

Structure of the O-specific polysaccharide of Proteus mirabilis O16 containing ethanolamine phosphate and ribitol phosphate

The O-specific polysaccharide of Proteus mirabilis O16 was studied by 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, NOESY, H-detected 1H,13C HMQC, HMQC-TOCSY, and 1H,31P HMQC experiments, along with chemical methods. The polysaccharide was found to be a ribitol teichoic acid-like polymer having the following structure [structure: see text].