Complementary binding sites

Amino-5 -deoxy-2, 3 -0-isopropylideneadenosine was acylated at N-5 with an activated derivative of the 6-carboxy-2-naphthyl ester of Kemp s acid imide. The resulting molecule possesses self-complementary binding sites, the key feature of replicating molecules that act as templates for their own reproduction. The dimer of this molecule is, however, not very stable K = 630 L mol ). When the two initially mentioned educts are added, a small proportion of the ternary complex is also formed and undergoes a fast, template-catalysed... 

Scheme 2.4 Single defined heterodimeric catalysts from mixing and self-assembly of monodentate ligands with complementary binding sites in the presence of a metal source.

Figure 2.2 Ligand library of mxn different and defined heterodimeric ligands through mixing of two sets of monodentate ligands with complementary binding sites.

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). 

Unlike the cyclic catenanes, rotaxanes are simpler species originally proposed by Wasserman and first demonstrated by Harrison [77], In these systems a cyclic molecule is threaded on a rigid or flexible molecular axle, attracted by complementary binding sites, to form a pseudorotaxane. Under normal entropically driven supramolecular chemistry the cyclic component would eventually slip off one or other end of the central axle, however, it can be kept in place if both ends of the axle react with bulky groups while the macrocycle is still threaded. Alternatively a macrocycle can be formed around an axle molecule that already possesses bulky termini, as shown in Fig. 1.22. Either method leads to an entanglement in which the cycle species can move along the thread without ever coming off. 

In these aggregation phenomena, the formation of intermacromolecular complexes is attributed to the fact that macromolecules with complementary binding sites interact with each other almost stoichiometrically in solution due to certain secondary binding forces. In this review, the formation of complementary complexes in synthetic macromolecular systems is mainly discussed. 

Gel formation could be switched off either by dilution with water or by addition of monomeric P-CD or guest [190], Several other polymeric systems, with complementary binding sites conjugated to polyacrylic acid [194,203], polyacryl amide [204], and chitosan [205-207] backbones, have been described subsequently, all with similar properties. Compared to regular covalent networks, these noncova-lent, supramolecular networks offer several advantages ... 

Kuroda et al. have reported a porphyrin-based molecular trench (Figure 74) with highly complementary binding sites for tartaric acid dialkyl esters showing association constants as high as 10 M [100]. 

In the 1980s the Hamilton group applied the idea of complementary binding sites to the detect barbiturate derivatives. Barbiturates have alternating ketone and... 

Most MIPs are synthesized as three-dimensional polymer networks in which functional monomers, arranged around a template, are fixed in position by copolymerization with a cross-linker. The spatial arrangement of the monomers creates complementary binding sites capable of rebinding the template. 

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