Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Shigella dysenteriae [ICD11:
XN285 
];
infection due to Escherichia coli [ICD11:
XN6P4 ]
The structure was elucidated in this paperNCBI PubMed ID: 17905981Journal NLM ID: 2985120RPublisher: American Society for Microbiology
Correspondence: fenglu63
nankai.edu.cn
Institutions: TEDA School of Biological Sciences and Biotechnology, Nankai University,1 Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Research Center for Functional Genomics and Biochip, 23 Hongda Street, TEDA, Tianjin 300457, People’s Republic ofChina, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, TEDA School of Biological Sciences and Biotechnology, Nankai University,1 Tianjin Key Laboratory of Microbial Functional Genomics, Tianjin Research Center for Functional Genomics and Biochip, 23 Hongda Street, TEDA, Tianjin 300457, People’s Republic of China, N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
O antigen variation due to the presence of different types of sugars and sugar linkages is important for the survival of bacteria against host immune systems. The O antigens of S. dysenteriae type 7 and E. coli O7 contain 4-(N-acetylglycyl)amino-4,6-dideoxy-D-glucose (D-Qui4NGlyAc) and 4-acetamido-4,6-dideoxy-D-glucose (D-Qui4NAc), respectively, which are sugars not often found in studied polysaccharides. In this study, we characterized the biosynthetic pathways for dTDP-D-Qui4N and dTDP-D-Qui4NAc (the nucleotide-activated precursors of D-Qui4NGlyAc and D-Qui4NAc in O antigens). Predicted genes involved in the synthesis of the two sugars were cloned, and the gene products were overexpressed and purified as His-tagged fusion proteins. In vitro enzymatic reactions were carried out using the purified proteins, and the reaction products were analyzed by capillary electrophoresis, electrospray ionization mass spectrometry, and nuclear magnetic resonance spectroscopy. It was shown that in S. dysenteriae type 7 and E. coli O7 dTDP-D-Qui4N is synthesized from α-D-glucose-1-phosphate in three reaction steps catalyzed by glucose-1-phosphate thymidyltransferase (RmlA), dTDP-D-glucose 4,6-dehydratase (RmlB), and dTDP-4-keto-6-deoxy-D-glucose aminotransferase (VioA), respectively. An additional acetyltransferase (VioB) catalyzes the conversion of dTDP-D-Qui4N into dTDP-D-Qui4NAc in E. coli O7. Kinetic parameters and some other properties of VioA and VioB are described and differences between VioA proteins from S. dysenteriae type 7 and E. coli O7 discussed. To our knowledge, this is the first time that functions of VioA and VioB have been biochemically characterized. This study provides valuable enzyme sources for the production of dTDP-D-Qui4N and dTDP-D-Qui4NAc, which are potentially useful in pharmaceutical industry for drugs development
biosynthesis, Escherichia coli, Shigella dysenteriaes
Structure type: monomer
Location inside paper: p.8632
Trivial name: dTDP-6-deoxy-D-xylohex-4-ulose, dTDP-4-keto-6-deoxy-α-D-glucose, dTDP-6-dideoxy-xylo-hexos-4-ulose, dTDP-6-deoxy-α-D-xylo-hex-4-ulose, dTDP-4-oxo-6-deoxy-α-D-glucose, dTDP-6-deoxy-D-xylo-hex-4-ulopyranose, dTDP-4-keto-6-deoxy-D-glucose, dTDP-4-keto-6-deoxyglucose
Compound class: nucleoside diphosphate sugar
Contained glycoepitopes: IEDB_138113,IEDB_196259
Methods: 1H NMR, NMR-2D, 31P NMR, ESI-MS, MS, genetic methods, biochemical methods, HPLC, capillary electrophoresis (CE)
Enzymes that release or process the structure: dTDP-D-glucose 4,6-dehydratase (RmlB)
Biosynthesis and genetic data: genetic data, biochemical data
Synthetic data: enzymatic
Comments, role: dTDP-D-Glc4O is intermediate in biosynthesis of dTDP-D-Qui4N
Related record ID(s): 20526, 21420, 21584, 21689, 21691, 21692, 23100, 23229, 23326, 24136
NCBI Taxonomy refs (TaxIDs): 622,
2162916
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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