Carbohydrates hydrogen bonding

The crystal structure of 5-chloro-2-deoxyuridine [CLDOUR] has a very simple pattern with two infinite chains (Fig. 17.21). One is through the O -H groups, and the other through the minor component of a three-center bond formed by 0(30-H. It strongly resembles a carbohydrate hydrogen-bonding pattern. A very simple scheme is also formed by 2-chloro-2 -deoxyuridine [CDURID] with a short finite chain and a separate link from the primary alcohol (Fig. 17.22). 

Carbohydrate Force Fields Carbohydrates Hydrogen Bonding 2 Molecular Dynamics DNA Molecular Dynamics Simulations of Nucleic Acids Molecular Dynamics Techniques and Applications to Proteins Solvation Modeling Water Clusters. 

Section 28 8 The most common form of DNA is B DNA which exists as a right handed double helix The carbohydrate-phosphate backbone lies on the outside the punne and pyrimidine bases on the inside The double helix IS stabilized by complementary hydrogen bonding (base pairing) between adenine (A) and thymine (T) and guanine (G) and cytosine (C)... 

All of these functions are made possible by the characteristic chemical features of carbohydrates (1) the existence of at least one and often two or more asymmetric centers, (2) the ability to exist either in linear or ring structures, (3) the capacity to form polymeric structures via glyeosidie bonds, and (4) the potential to form multiple hydrogen bonds with water or other molecules in their environment. 

Three types of carbohydrate sample have been reported to give data above mass 4000, namely, permethylated polysaccharides, permethylated glycosphingolipids, and naturally acylated forms of a mycobacterial O-methyl-D-glucose polysaccharide. All are hydrophobic, and desorption is probably facilitated by their inability to form strongly hydrogen-bonded aggregates, either with themselves or with the matrix. 

Some phosphines are easily soluble in water due to their strong hydrogen-bonding capacity. Representatives of these ligands are l,3,5-triaza-7-phosphaadaman-tane (pta), the polyoxyethylene-substituted and the carbohydrate-derived phosphines. A detailed compilation of water-soluble phosphines (together with the known solubilities) can be found in [4],... 

Ludwig s (2001) review discusses water clusters and water cluster models. One of the water clusters discussed by Ludwig is the icosahedral cluster developed by Chaplin (1999). A fluctuating network of water molecules, with local icosahedral symmetry, was proposed by Chaplin (1999) it contains, when complete, 280 fully hydrogen-bonded water molecules. This structure allows explanation of a number of the anomalous properties of water, including its temperature-density and pressure-viscosity behaviors, the radial distribution pattern, the change in water properties on supercooling, and the solvation properties of ions, hydrophobic molecules, carbohydrates, and macromolecules (Chaplin, 1999, 2001, 2004). 

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