Secondary hydrogen-bond interactions

Figure 1.18 (a) Primary and secondary hydrogen bond interactions between guanine and cytosine... 

Fig. 1 Examples of positive and negative secondary hydrogen bond interactions on the binding affinity between triple donor D and acceptor A hydrogen bond partners...

Fig. 3 Secondary hydrogen-bonding interactions. Attractive interactions are marked green, and repulsive interactions are marked red. 

Ribosomes, the supramolecular assemblies where protein synthesis occurs, are about 65% RNA of the ribosomal RNA type. Ribosomal RNA (rRNA) molecules fold into characteristic secondary structures as a consequence of intramolecular hydrogen bond interactions (marginal figure). The different species of rRNA are generally referred to according to their sedimentation coefficients (see the Appendix to Chapter 5), which are a rough measure of their relative size (Table 11.2 and Figure 11.25). 

Sidechain conservatism may be split up into at least two kinds 1) substitutions which conserve sidechain bonding forces - providing similar electrostatic, hydrophilic, or hydrogen bonding interactions, and 2) substitutions conserving secondary structure propensity. For instance, substitution of glutamic acid with aspartic acid conserves charge, but this could have a considerable effect upon the secondary structure propensity of the peptide. 

Hydrogen bonding interactions are important for the development of selfassembling supramolecular materials, which are defined as materials in which monomeric units are reversibly bound via secondary interactions to form polymer-like stmctures that exhibit polymeric properties in solution as well as in bulk (Bmnsveld et al. 2001). Rotello used hydrogen bond functional polymers to direct the formation of large vesicles (lUian et al. 2000), reversibly attach polymers on... 

Hydrogen-bonding interactions are considerably weaker than ionic interactions and covalent bonds but have a profound effect on many chemical and physical properties [221] and determine the shapes of large molecules such as proteins and nucleic acids. Protein secondary structure is determined by H bonding between the carbonyl oxygen of one amide unit and the N—H bond of another. The two strands of the double helix of... 

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