Multiple noncovalent interactions

Having discussed self-assembly strategies toward noncovalently functionalized side chain supramolecular polymers as well as studies toward the orthogonahty of using multiple noncovalent interactions in the same system, this section presents some of the potential applications of these systems as reported in the literature. The apphcations based on these systems can be broadly classified into two areas 1) self-assembled functional materials and 2) functionalized reversible network formation. 

In Mb, heme is located in the heme pocket via multiple noncovalent interactions such as Fe-His coordination, hydrophobic contacts with several nonpolar amino acid residues, and hydrogen bonding between heme propionates and polar amino acids (69). Therefore, the hemin can be easily removed from the heme pocket under acidic conditions to give apomyoglobin (apoMb) (70, 71). Over the past three decades, a variety of artificial iron porphyrins and porphyrinoids have been incorporated into the apoprotein to reconstitute the... 

A second example where multiple noncovalent interactions have been employed and that is motivated by biological systems is the employment of lipid bi-... 

The self-assembly of small molecules into complex material based on a multitude of different noncovalent interactions, such as hydrogen bonding, ionic interactions, hydrophobicity and metal coordination, has been established over the last century [2, 30, 38, 44-49]. In this context, the real power of self-assembly becomes evident when not only multiple noncovalent interactions but also multiple levels of self-assembly occur within the same small molecule system. These multiple tiers of self-organizational hierarchy can yield highly complex structures with sec-... 

The essential realization in this spontaneous ordering process is the importance of noncovalent bonding interaction between molecules, that is, supramolecular chemistry. These conformation-specific interactions are governed by weak forces including hydrogen bonding, metal coordination, van der Waals forces, pi-pi interactions, and electrostatic Coulombic effects. The cooperative action of multiple noncovalent interaction forces is precisely the path nature takes to produce shape and form. 

The a -amino group of the amino acid substrate displaces the e-amino group of the active-site lysine residue. In other words, an internal aldimine becomes an external aldimine. The amino acid-PLP Schiff base that is formed remains tightly bound to the enzyme by multiple noncovalent interactions. 

A FIGURE 2-10 Molecular complementarity and the binding of proteins via multiple noncovalent interactions. The... 

Molecular complementarity is the lock-and-key fit between molecules whose shapes, charges, and other physical properties are complementary. Multiple noncovalent interactions can form between complementary molecules, causing them to bind tightly (see Figure 2-10), but not between molecules that are not complementary. 

Eq. (4) can be generalized to multivalent systems that make multiple noncovalent interactions (Eq. (5)). 

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