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The chair conformation of six-membered rings have a dihedral angle of 60° between adjacent substituents thus usually making it the most stable conformer. Since there are two possible chair conformation steric and stereoelectronic effects such as the anomeric effect, 1,3-diaxial interactions, dipoles and intramolecular hydrogen bonding must be taken into consideration when looking at relative ...
Typical 1 H NMR chemical shifts of carbohydrate ring protons are 3–6 ppm (4.5–5.5 ppm for anomeric protons). Typical 13 C NMR chemical shifts of carbohydrate ring carbons are 60–110 ppm In the case of simple mono- and oligosaccharide molecules, all proton signals are typically separated from one another (usually at 500 MHz or better NMR ...
A Haworth projection has the following characteristics: [3] Carbon is the implicit type of atom. In the example on the right, the atoms numbered from 1 to 6 are all carbon atoms. Carbon 1 is known as the anomeric carbon. Hydrogen atoms on carbon are implicit. In the example, atoms 1 to 6 have extra hydrogen atoms not depicted.
Structural alignment techniques have traditionally been applied exclusively to proteins, as the primary biological macromolecules that assume characteristic three-dimensional structures. However, large RNA molecules also form characteristic tertiary structures , which are mediated primarily by hydrogen bonds formed between base pairs as well as ...
The myoglobin 3-dimensional structure is made up of 8 alpha-helices, and the crystal structure showed that their conformation was right-handed and very closely matched the geometry proposed by Linus Pauling, with 3.6 residues per turn and backbone hydrogen bonds from the peptide NH of one residue to the peptide CO of residue i+4.
[3] A specific nonlinear optical technique called second-harmonic generation (SHG) has been recently applied to the study of conformational change in proteins. [ 4 ] In this method, a second-harmonic-active probe is placed at a site that undergoes motion in the protein by mutagenesis or non-site-specific attachment, and the protein is adsorbed ...
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The ω angle at the peptide bond is normally 180°, since the partial-double-bond character keeps the peptide bond planar. [3] The figure in the top right shows the allowed φ,ψ backbone conformational regions from the Ramachandran et al. 1963 and 1968 hard-sphere calculations: full radius in solid outline, reduced radius in dashed, and ...