Microbial Polysaccharides**This article is dedicated to Professor Michael Heidelberger, New York, the great pioneer of polysaccharide immunochemistry.

Jann, Klaus; Westphal, Otto

doi:10.1016/b978-0-12-635503-1.50008-5

Cited by 56 publications

(7 citation statements)

References 427 publications

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“…(Gray et al, 2000); plant symbiotic rhizobacteria (Forsberg and Carlson, 1998); aerobic bacteria from the deep sea (Raguénès et al, 2003); and the hyperthermophilic bacterium Aquifex pyrophilus (Plö tz et al, 2000). The existence of GalA is not restricted to Gram-negative bacteria being present in the capsular polysaccharide of the Gram-positive human pathogen type-I Streptococcus pneumoniae Stroop et al, 2002; for review, see Jann and Westphal, 1975), as well as in certain polysaccharides of the Cyanobacterium spp. (Gloaguen et al, 1995).…”

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confidence: 99%

The Biosynthesis of UDP-Galacturonic Acid in Plants. Functional Cloning and Characterization of Arabidopsis UDP-d-Glucuronic Acid 4-Epimerase

Bar‐Peled

2004

Plant Physiology

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UDP-GlcA 4-epimerase (UGlcAE) catalyzes the epimerization of UDP-α-d-glucuronic acid (UDP-GlcA) to UDP-α-d-galacturonic acid (UDP-GalA). UDP-GalA is a precursor for the synthesis of numerous cell-surface polysaccharides in bacteria and plants. Using a biochemical screen, a gene encoding AtUGlcAE1 in Arabidopsis (Arabidopsis thaliana) was identified and the recombinant enzyme biochemically characterized. The gene belongs to a small gene family composed of six isoforms. All members of the UGlcAE gene family encode a putative type-II membrane protein and have two domains: a variable N-terminal region approximately 120 amino acids long composed of a predicted cytosolic, transmembrane, and stem domain, followed by a large conserved C-terminal catalytic region approximately 300 amino acids long composed of a highly conserved catalytic domain found in a large protein family of epimerase/dehydratases. The recombinant epimerase has a predicted molecular mass of approximately 43 kD, although size-exclusion chromatography suggests that it may exist as a dimer (approximately 88 kD). AtUGlcAE1 forms UDP-GalA with an equilibrium constant value of approximately 1.9 and has an apparent Km value of 720 μm for UDP-GlcA. The enzyme has maximum activity at pH 7.5 and is active between 20°C and 55°C. Arabidopsis AtUGlcAE1 is not inhibited by UDP-Glc, UDP-Gal, or UMP. However, the enzyme is inhibited by UDP-Xyl and UDP-Ara, suggesting that these nucleotide sugars have a role in regulating the synthesis of pectin. The cloning of the AtUGlcAE1 gene will increase our ability to investigate the molecular factors that regulate pectin biosynthesis in plants. The availability of a functional recombinant UDP-GlcA 4-epimerase will be of considerable value for the facile generation of UDP-d-GalA in the amounts required for detailed studies of pectin biosynthesis.

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confidence: 99%

The Biosynthesis of UDP-Galacturonic Acid in Plants. Functional Cloning and Characterization of Arabidopsis UDP-d-Glucuronic Acid 4-Epimerase

Bar‐Peled

2004

Plant Physiology

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“…This is discussed with respect to the overall mechanism of the biosynthesis of the 0 9 antigen. The 0 9 antigen of Eschevichia coli is a lipopolysaccharide which has an a-mannan as the O-specific polysaccharide moiety (for definitions and further information see [1,2] . Thus, the synthesis of the 0 9 antigen differs from that of the other enterobacterial 0 antigens hitherto described [3,4].…”

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confidence: 99%

“…The 0 9 antigen of Eschevichia coli is a lipopolysaccharide which has an a-mannan as the O-specific polysaccharide moiety (for definitions and further information see [1,2]). The structure of the polysaccharide was reported recently [3].…”

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Biosynthesis of the 09 Antigen of Escherichia coli. Growth of the Polysaccharide Chain

Flemming

Jann

1978

Eur J Biochem

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The 09-specific mannan of Eschericlzia coli was synthesized in vitro from GDP-['4C]mannose by membranes which were obtained from a phosphomannose isomerase-less mutant of E. coli 09:K29-: H -. Subsequent treatment of the membranes with dilute acid liberated a neutral prodfict, whereas with aqueous phenol a charged product was obtained. Chromatography on DEAE-cellulose, incubation with alkaline phosphatase and microdetermination showed that the charged mannan was substituted with one phosphate per chain.The neutral 14C-labelled product of the incubation in vitro was reduced with sodium b~ro [~H]hydride. After total acid hydrolysis, the radioactive material was chromatographed on paper in the presence of borate. It was found that [3H]glucitol, but no [3H, 14C]mannitol was present. When the neutral product, which was obtained after incubation of 14C-prelabelled membranes with nonradioactive GDP-mannose, was hydrolyzed with and without prior reduction with non-radioactive sodium borohydride, in subsequent paper chromatography, ['4C]glucitol or [14C]glucose was found. The glucose was also converted enzymatically to gluconic acid, which was identified by paper electrophoresis. These results show that in the neutral 09-specific mannan glucose is at the reducing end and they indicate that the mannan chain grows at the non-reducing end. This is discussed with respect to the overall mechanism of the biosynthesis of the 0 9 antigen. The 0 9 antigen of Eschevichia coli is a lipopolysaccharide which has an a-mannan as the O-specific polysaccharide moiety (for definitions and further information see [1,2] . Thus, the synthesis of the 0 9 antigen differs from that of the other enterobacterial 0 antigens hitherto described [3,4]. Bray and Robbins [S] have shown that the O-specific polysaccharide from Salmonella anaturn, which is assembled from undecaprenyl-pyrophosphoryl oligosaccharides grows at the reducing end. We were interested in the mode of chain elongation of the 0 9 mannan and its linkage to the cytoplasmic membrane during biosynthesis. Therefore we have analyzed the material synthesized in vitro and found that according to the method of liberation from the membrane, the mannan is either neutral or charged. The charge proved to be due to phosphate substitution. Using reduction with sodium borohydride, we could show that the reducing end of the neutral mannan is not mannose, but glucose. These results are described in the present communication and they are discussed with respect to the direction of chain elongation and possible overall mechanisms of the 0 9 mannan biosynthesis. Amersham-Buchler (BraunschweigWenden). Alkaline phosphatase and glucose oxidase were from Boehringer (Mannheim). MATERIALS AND METHODS Chemicals and Enzymes Bacteria and CultivationAs described previously [7] E. coli F860, a mutant of E. coli F397 ( 0 9 : K29Y: H-) lacking phosphoman-

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“…A quite different structure for E. coli RI core has been proposed, however, by Jann et al as reported by Jann and Westphal [24] and Galanos et al [25]. This structure has the same sugar constituents as the structure discussed previously but in a different sequence.…”

Section: Discussionmentioning

confidence: 67%

Structure of the Hexose Region of Shigella sonnei Phase II Lipopolysaccharide with 3-Deoxy-d-manno-octulosonic Acid as Possible Immunodeterminant and Its Relation to Escherichia coli R1 Core

Kontrohr

Kocsis

1978

Eur J Biochem

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Microbial Polysaccharides**This article is dedicated to Professor Michael Heidelberger, New York, the great pioneer of polysaccharide immunochemistry.

Cited by 56 publications

References 427 publications

The Biosynthesis of UDP-Galacturonic Acid in Plants. Functional Cloning and Characterization of Arabidopsis UDP-d-Glucuronic Acid 4-Epimerase

The Biosynthesis of UDP-Galacturonic Acid in Plants. Functional Cloning and Characterization of Arabidopsis UDP-d-Glucuronic Acid 4-Epimerase

Biosynthesis of the 09 Antigen of Escherichia coli. Growth of the Polysaccharide Chain

Structure of the Hexose Region of Shigella sonnei Phase II Lipopolysaccharide with 3-Deoxy-d-manno-octulosonic Acid as Possible Immunodeterminant and Its Relation to Escherichia coli R1 Core

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