Hydrogen bonding continued nucleic acids

Fig. 16. An unusual interrupted helix from subtilisin (residues 62-86), in which the helical hydrogen bonds continue to a final tum that is formed by a separate piece of main chain. Such interrupted helices (broken on one side of the double helix) are apparently a fundamental feature of nucleic acid structure as illustrated by tRNA, but are exceedingly rare in protein structure.

Note how many distances have to be uniform in order to properly align the hydrogen bonds that stabilize the DNA helix. Here the principle of bonding orbitals is continued to the next higher level of molecular association. The next step, the covalent linkage of the bases of nucleic acid to polynucleotides, is the moment when potential memory is produced from molecules that singularly have no meaning. 

Since its first suggestion many years ago , the hydrogen bond has continued to fascinate chemists. This interaction is intimately involved in the structure and properties of water in its various phases, and of molecules in aqueous solution. In addition to the traditional role of the H-bond as a structural element in large molecules such as proteins and nucleic acids °, a series of such bonds appear to be vital to the functioning of a number of en-... 

Hydrogen bonding in (Continued diamine, diol mixtures, 138 ethanolamine, 282 nucleic acids, 137-138 proteins, 137-138 water dimer, 138 water trimer, 139... 

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