Biomaterial Database

Model studies on dental plaque formation: deoxyhexoses in Actinomyces viscosus. 1979

C A Tylenda, and D Charon, and F P Lombardi, and O Gabriel

A careful examination of two strains of Actinomyces viscosus, T14V (virulent) and T14AV (avirulent), revealed no qualitative or quantitative difference in 6-deoxyhexose content of their cell surface. For a further study of the role of these sugars in cell surface-related phenomena, the stereochemical configuration of deoxyhexoses of A. viscosus T14 was established by two complementary approaches. (i) Examination of the biosynthetic pathway was found to lead to the formation of both 6-deoxy-l-talose and 6-deoxy-l-mannose and showed no differences in the ability of either bacterial strain, A. viscosus T14V or T14AV, to produce the precursors of these cell wall components. The biosynthetic pathway for 6-deoxy-l-talose and 6-deoxy-l-mannose was found to originate from deoxy-thymidine diphosphate (dTDP)-d-glucose, which in turn is converted to dTDP-4-keto-6-deoxy-d-glucose. Epimerization at carbons 3 and 5 of the hexose moiety of dTDP-4-keto-6-deoxy-d-glucose is followed by stereospecific reduction with reduced nicotinamide adenine dinucleotide phosphate to yield dTDP-6-deoxy-l-talose and dTDP-6-deoxy-l-mannose. In cell-free extracts of both A. viscosus T14 and T14AV, an identical ratio of 6-deoxy-l-talose to 6-deoxy-l-mannose of 1:8 was produced. Known precursors for the d-isomers of the same 6-deoxyhexoses such as guanosine diphosphate-d-mannose and dTDP-d-mannose were not converted by A. viscosus T14 cell-free extracts. (ii) Isolation of 6-[U-(14)C]deoxytalose and 6-[U-(14)C]deoxymannose from both strains of A. viscosus T14 was carried out by growing cells in a medium containing d-[U-(14)C]glucose. Again no qualitative or quantitative difference was noticeable between the two strains when 6-deoxy-hexoses were released from whole cells or purified cell walls by acid hydrolysis. Radioactive 6-[U-(14)C]deoxytalose isolated from the cell surface was used in an isotope dilution experiment to establish the stereochemical configuration of this 6-deoxyhexose. The radioactive sugar was mixed with unlabeled standard d- or l-6-deoxyhexose, respectively, and conversion to the corresponding 1-phenylflavazole derivative was carried out. Recrystallization to constant specific activity identified the radioactive sugar isolated from A. viscosus to be the l-isomer. A facile synthesis of the rare sugars 6-deoxy-l-talose and 6-deoxy-d-talose is reported.

UI	MeSH Term	Description	Entries
D008968	Molecular Conformation	The characteristic three-dimensional shape of a molecule.	Molecular Configuration,3D Molecular Structure,Configuration, Molecular,Molecular Structure, Three Dimensional,Three Dimensional Molecular Structure,3D Molecular Structures,Configurations, Molecular,Conformation, Molecular,Conformations, Molecular,Molecular Configurations,Molecular Conformations,Molecular Structure, 3D,Molecular Structures, 3D,Structure, 3D Molecular,Structures, 3D Molecular
D009702	Nucleoside Diphosphate Sugars		Diphosphate Sugars, Nucleoside,Sugars, Nucleoside Diphosphate
D002473	Cell Wall	The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.	Cell Walls,Wall, Cell,Walls, Cell
D002474	Cell-Free System	A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)	Cellfree System,Cell Free System,Cell-Free Systems,Cellfree Systems,System, Cell-Free,System, Cellfree,Systems, Cell-Free,Systems, Cellfree
D003837	Deoxy Sugars	Sugars that in which one or more hydroxyl groups of the pyranose or furanose ring is substituted by hydrogen.	Deoxy Sugar,Sugar, Deoxy,Sugars, Deoxy
D003847	Deoxyglucose	2-Deoxy-D-arabino-hexose. An antimetabolite of glucose with antiviral activity.	2-Deoxy-D-glucose,2-Deoxyglucose,2-Desoxy-D-glucose,2 Deoxy D glucose,2 Deoxyglucose,2 Desoxy D glucose
D005643	Fucose	A six-member ring deoxysugar with the chemical formula C6H12O5. It lacks a hydroxyl group on the carbon at position 6 of the molecule.	Deoxygalactose,alpha-Fucose,alpha Fucose
D000190	Actinomyces	A genus of gram-positive, rod-shaped bacteria whose organisms are nonmotile. Filaments that may be present in certain species are either straight or wavy and may have swollen or clubbed heads.
D012210	Rhamnose	A methylpentose whose L- isomer is found naturally in many plant glycosides and some gram-negative bacterial lipopolysaccharides.	Deoxymannose,Rhamnose, L-Isomer,Rhamnose, L Isomer
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species