CSDB: Search results

References to other databases: GTC:G30068VP, GlycomeDB:5771
Structural formula & atomic coordinates
Sweet-II 3D model
Show glycosyltransferases

3-Deoxy-D-manno-oct-2-ulosonic acid (Kdo) transferases (KdtA) are multifunctional glycosyltransferases with primary structures of low similarity. Totally degenerated primers were deduced from two stretches of identical amino acids between known KdtA sequences and used to amplify by PCR a kdtA-specific fragment from Acinetobacter baumannii ATCC 15308 DNA which was then applied as a probe for the cloning and sequencing of the complete Kdo transferase gene. With conserved PCR primers for this structural gene from A. baumannii ATCC 15308, also kdtA genes of A. baumannii ATCC 19606 and A. haemolyticus ATCC 17906 were obtained, cloned from the chromosome and sequenced. The genes coded for proteins with similarities to known Kdo transferases. Within the genus Acinetobacter, the identity and similarity of the deduced amino acid sequences were 71% and 84.5%, respectively. The kdtA sequences of both A. baumannii strains were identical and possessed a TTG start codon, whereas ATG was found in the case of A. haemolyticus. The genes from Acinetobacter and kdtA from Escherichia coli K-12 were expressed in the Gram-positive bacterium Corynebacterium glutamicum. In vitro tests confirmed the function of the gene products as Kdo transferases, which transferred mainly two Kdo residues to a synthetic lipid A precursor of E. coli. Also, no differences between the cloned kdtA genes from A. baumanniii, A. haemnolyticus and E. coli were observed when tetraacyl or hexaacyl lipid A were tested, since all transferases acted more efficiently on the former. With limiting amounts of acceptor, all Kdo transferases were able to transfer a third Kdo residue with varying efficiency

gene, characterization, 3-deoxy-D-manno-oct-2-ulosonic acid, acid, Acinetobacter, Acinetobacter baumannii, Acinetobacter haemolyticus, cloning, Kdo, lipopolysaccharide biosynthesis, shuttle plasmid, transferase

NCBI PubMed ID: 9660198
Publication DOI: 10.1046/j.1432-1327.1998.2540404.x
Journal NLM ID: 0107600
Publisher: Oxford, UK: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
Correspondence: hbrade@fz-borstel.de
Institutions: Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
Methods: PCR, DNA sequencing, DNA cloning

Lipopolysaccharides (LPSs) of Chlamydophila psittaci 6BC and Chlamydophila pneumoniae Kajaani 6 contain 3-deoxy-D-manno-oct-2- ulosonic acid (Kdo), GlcN, organic bound phosphate, and fatty acids in the molar ratios of approximately 3:2:2.2:4.8 and approximately 2.9:2:2.1:4.9, respectively. The LPSs were immunoreactive with a monoclonal antibody against a family-specific epitope of chlamydial LPS. This finding, together with methylation analyses of both LPSs and MALDI-TOF MS experiments on de-O-, and de-O,N-acylated LPSs, indicate the presence of a Kdo trisaccharide proximal to lipid A having a structure α-Kdo-(2→8)-α-Kdo-(2→4)-α-Kdo, which appears to be the main component of the core region in the native chlamydial LPSs. In the de-O-acylated LPSs from Chl. psittaci 6BC and Chl. pneumoniae Kajaani 6, two major molecular species are present that differ in distribution of amide-bound hydroxy fatty acids over both GlcN. It appears that either two (R)-3-hydroxy-18-methylicosanoic acids or one (R)-3-hydroxy-18-methylicosanoic acid and one (R)-3- hydroxyicosanoic acid are attached to the GlcN residues. In contrast, the de-O-acylated LPS of Chl. psittaci PK 5082 contains one major molecular species that has two (R)-3-hydroxyicosanoic acid residues attached to two GlcN residues

Lipopolysaccharide, structure, Chlamydophila psittaci, chemical composition, Chlamydophila pneumoniae

NCBI PubMed ID: 11705470
Journal NLM ID: 0043535
Publisher: Elsevier
Correspondence: virutoma@nic.savba.sk
Institutions: Department of Rickettsiology and Chlamydiology, Institute of Virology, Slovak Academy of Sciences, Dubravska cesta 9, 842 45 Bratislava, Slovak Republic
Methods: methylation, GC-MS, MALDI-TOF MS, HPLC, PAGE

Lipopolysaccharides (LPS) are the endotoxins of Gram-negative bacteria and very well known for their immunological, pharmacological and pathophysiological effects displayed in eucaryotic cells and organisms. To date, much emphasis has been put on the elucidation of the chemical structures of LPS and on their relation, or that of substructures, to the various biological effects. The lipid part of LPS, the lipid A, was proven to represent the toxic principle of endotoxin. However, lipid A toxicity depends strongly on its structure, and is influenced by a second region of LPS, the core region, that is covalently linked to lipid A. Also, the core region possesses immunogenic properties. Therefore, complete structural analyses of the core region and the comparison of its structures with biological features of LPS are of high importance for a better understanding of LPS action, and one prerequesite for strategies aimed at the treatment of endotoxicosis. In the past, quite a number of structures of the core regions from various Gram-negative bacteria were published and summarized in several overviews. The present review adds to this knowledge those structures that were published between October 1998 and December 2001.

lipopolysaccharides, heptose, Kdo, chemical structure, core region, tructure

Publication DOI: 10.4052/tigg.14.87
Journal NLM ID: 9425898
Correspondence: oholst@fz-borstel.de
Institutions: Structural Biochemistry, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany

On the basis of high-resolution crystal structures of the antigen binding fragment of the chlamydia-specific monoclonal antibody S25-2 in complex with the trisaccharide α-Kdop-(2→8)-α-Kdop-(2→4)-α-Kdop and part structures thereof, seven modified α-Kdop-(2→8)-α-Kdop disaccharide derivatives were synthesized starting from the protected disaccharide allyl ketoside 1. Hydroboration and subsequent oxidation as well as ozonolysis, respectively, followed by Wittig-reaction for chain elongation were used to install a terminal carboxylic group on spacer entities of various chain lengths. Furthermore, addition of methyl 2-thioacetate to the allyl group furnished the corresponding thioether derivative. Standard deprotection gave the target disaccharides as simplified trisaccharide analogues, which will be used to probe the contribution of the proximal carboxylic group in the binding of chlamydia-specific di- and trisaccharide-reactive monoclonal antibodies.

Lipopolysaccharide, synthesis, trisaccharide, Kdo, antibody, epitope, spacer, chlamydial

NCBI PubMed ID: 17007824
Journal NLM ID: 0043535
Publisher: Elsevier
Correspondence: paul.kosma@boku.ac.at
Institutions: Department of Chemistry, University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
Methods: 13C NMR, 1H NMR, ESI-MS, chemical methods

Early steps in the biosynthesis of lipopolysaccharide (LPS) involve the transfer of 3-deoxy-α-D-manno-oct-2-ulopyranosonic acid (Kdo) to lipid A. Whereas Kdo transferases (WaaA) of Escherichia coli generate a (2→4)-linked Kdo disaccharide, Chlamydiae contain tri- or tetra-functional WaaA generating oligosaccharides with (2→8)- and (2→4)-linkages between Kdo. It has been suggested that the transfer of L-glycero-α-D-manno-heptose (Hep) to Kdo by an E. coli WaaC may not be possible in the presence of (2→8)-linked Kdo. E. coli double-mutants deficient in heptosyltransferases I (waaC) and II (waaF) and expressing waaA of Chlamydiae instead of their own, make Chlamydia-type Kdo oligosaccharides which are attached to an E. coli lipid A. Using such strains expressing waaA of Chlamydophila pneumoniae, Chlamydophila psittaci, or Chlamydia trachomatis, we have studied the effect of E. coli waaC gene expression on LPS structure. Structural analyses revealed the formation of two novel oligosaccharides Hep-(1→5)[Kdo-(2→4)]-Kdo and Hep-(1→5)[Kdo-(2→8)-Kdo-(2→4)]-Kdo showing that Hep is transferred in the presence of (2→8)-linked Kdo. Surprisingly, the transfer of Hep onto Kdo-(2→4)-Kdo-(2→4)-Kdo did not occur, despite the fact that Hep-(1→5)[Kdo-(2→4)-Kdo-(2→4)]-Kdo is found in nature as a partial structure of E. coli LPS. The premature end of the biosynthesis and incorporation of Hep into the LPS indicated that WaaC had access to the substrate before Kdo transfer was completed. We have observed differences between WaaA of C. trachomatis, C. pneumoniae and C. psittaci which indicate mechanistic differences between these Kdo transferases

biosynthesis, LPS, Escherichia coli, Kdo, Hep, WaaA, WaaC, WaaF, Chlamydiae

NCBI PubMed ID: 19201821
Journal NLM ID: 101469670
Publisher: Sage Publications
Correspondence: sml@fz-borstel.de
Institutions: Research Center Borstel, Leibniz Center for Medicine and Biosciences, Borstel, Germany
Methods: 13C NMR, 1H NMR, SDS-PAGE, 31P NMR, ESI-MS, ESI-FTICR-MS, Western blotting, composition analysis, genetic methods