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These A-B intermediate forms adopt the sugar pucker properties and/or the base conformation of both DNA forms. In one study, the characteristic C3'-endo pucker is found on the first three sugars of the DNA strand, while the last three sugars have a C2'-endo pucker, like B-DNA. [2]
Its favored conformation is at low water concentrations. A-DNAs base pairs are tilted relative to the helix axis, and are displaced from the axis. The sugar pucker occurs at the C3'-endo and in RNA 2'-OH inhibits C2'-endo conformation. [13] Long considered little more than a laboratory artifice, A-DNA is now known to have several biological ...
L-Ribose Fischer Projection. Ribose is a simple sugar and carbohydrate with molecular formula C 5 H 10 O 5 and the linear-form composition H−(C=O)−(CHOH) 4 −H. The naturally occurring form, d-ribose, is a component of the ribonucleotides from which RNA is built, and so this compound is necessary for coding, decoding, regulation and expression of genes.
One example of a Z-DNA binding protein is the vaccinia E3L protein, which is a product of the E3L gene and mimics a mammalian protein that binds Z-DNA. [ 37 ] [ 38 ] Not only does the E3L protein have affinity to Z-DNA, it has also been found to play a role in the level of severity of virulence in mice caused by vaccinia virus, a type of poxvirus .
The altered conformation makes yDNA more similar to B-DNA in its orientation by changing the interstrand hydrogen bonds. Stability is highly dependent on the bases' rotation about the link between the base and the sugar of the backbone. yDNA's altered preference for this orientation makes it more stable overall than xDNA.
The ratio of the two anomers is specific for the regarding sugar. For example, regardless of the configuration of the starting D-glucose, a solution will gradually move towards being a mixture of approximately 64% β-D-glucopyranoside and 36% of α-D-glucopyranose.
Vicinal heteronuclear H-C-O-C coupling constants are used to study torsional angles along glycosidic bond between sugars or along exocyclic fragments, thus revealing a molecular conformation. Sugar rings are relatively rigid molecular fragments, thus vicinal proton-proton couplings are characteristic: Equatorial to axial: 1–4 Hz
The α- and β-anomers of D-glucopyranose.. In organic chemistry, the anomeric effect or Edward-Lemieux effect (after J. T. Edward and Raymond Lemieux) is a stereoelectronic effect that describes the tendency of heteroatomic substituents adjacent to a heteroatom within a cyclohexane ring to prefer the axial orientation instead of the less-hindered equatorial orientation that would be expected ...