Complementary-binding interactions

Conceptually, increasing the strength of the binding interactions between components that form D-A complexes can be achieved by changing the chemical structure and electronic nature of the D and A components (Fig. 2) or by increasing the number of co-operative, complementary binding interactions within a single complex (Fig. 3). 

Vernier principle A method to assemble multitopic binding parmers (i.e., hosts or guests having distinct and uneven numbers of complementary binding sites) into a supramolecule of well-defined dimensions possessing the maximum number of complementary binding interactions. 

Collectively, these thermal denaturation studies demonstrated that aPNAs bind to complementary ssDNA targets with high affinity and in a sequence-specific manner consistent with our proposed base-pairing model. Additional electrostatic and hydrophobic binding interactions can be incorporated into the aPNA design without affecting the primary Watson-Crick binding mode. 

Similar to micellar assemblies in water, reverse micelles have also been utilized to bring about nonspecific binding interactions in organic solvents. Akiyoshi et al. (2002) have synthesized an amphiphilic block copolymer containing PEO and an amylase chain as receptor for methyl orange (MO Chart 2.2). Amylases are insoluble and methoxy-PEO (MPEO) is soluble in chloroform. Hence, an MPEO-amylase block copolymer forms reverse micelles in chloroform. Akiyoshi et al. established the capability of the buried receptors to extract the complementary analyte by studying the ultraviolet visible (UV-vis) spectra. A solution of polymer was shaken... 

The remaining free hydroxy groups (e.g., 21 for /(-CD) can build up polar binding interaction sites, but they can also be derivatized. A vast number of CD derivatives has been synthesized and isolated with varying degrees of chemical specification they have modified physicochemical characteristics and stereoselectivity towards chiral complementary guest molecules. 

Fig. 5. Schematic diagram of complementary binding sites or knob-hole interactions in fibrin polymerization. Fibrinopeptides in the central domain cover knobs that are complementary to holes that are always exposed at the ends of the protein. When the fibrinopeptides are removed by thrombin, knob-hole interactions occur, giving rise to the two-stranded protofibril made up of half-staggered molecules.

Specific interactions between the A a complementary binding sites produce aggregates in which the fibrin monomers are half-staggered, since the central domain of one molecule binds to the end of the adjacent molecule (Fig. 5). Initially, a dimer is formed and then additional molecules are added to give a structure called the two-stranded protofibril (Fig. 3B) (Fowler et ai, 1981 Medved et ai, 1990). 

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