Supramolecular biology

Chemical approach to the study of supramolecular biological structure of chromatin, nucleoproteide complex of DNA 99UK365. 

To illustrate the supramolecular biological role of such molecular species we will look at the mode of action of acetylcholine (ACh, 2.8) in particular since this example highlights the profound effect that the non-covalent binding of a small molecular guest may have on a biological system. 

In many cases the metal is unusually close to the surface of the protein, unlike most enzymes, so that several enzymes can cooperate through a synergy, that perhaps exemplifies supramolecular biology, and to catalyse reactions that would be impossible with a single metal. 

Department of Supramolecular Biology Yokohama City University Yokohama, Japan... 

Supramolecular biological assemblies, like virus [52] or membrane fragments [261,262] containing bacteriorhodopsin have also been inserted in multilayers built by ESA. 

Clearly, the reactivity of a crystal and any attempt at a rational use of organic solid state chemistry as a systematic tool cannot be separated from a need to understand and manipulate the subtle intermolecular interactions which compose a crystal. In this chapter only a few of the reactions known to occur in a crystal have been touched upon. There are numerous reviews which highlight other types of reactions and aspects of reactivity. Similarly, only some of the intermolecular interactions which have been used to control the architecture of the crystal have been described. The interplay between these two areas, however, holds promise for the design of new synthetic pathways and the creation of complex supramolecular biologically related structures. 

The modem era of biochemistry and molecular biology has been shaped not least by the isolation and characterization of individual molecules. Recently, however, more and more polyfunctional macromolecular complexes are being discovered, including nonrandomly codistributed membrane-bound proteins [41], These are made up of several individual proteins, which can assemble spontaneously, possibly in the presence of a lipid membrane or an element of the cytoskeleton [42] which are themselves supramolecular complexes. Some of these complexes, e.g. snail haemocyanin [4o], are merely assembled from a very large number of identical subunits vimses are much larger and more elaborate and we are still some way from understanding the processes controlling the assembly of the wonderfully intricate and beautiful stmctures responsible for the iridescent colours of butterflies and moths [44]. 

A particular point of interest included in these hehcal complexes concerns the chirality. The heUcates obtained from the achiral strands are a racemic mixture of left- and right-handed double heUces (Fig. 34) (202). This special mode of recognition where homochiral supramolecular entities, as a consequence of homochiral self-recognition, result from racemic components is known as optical self-resolution (203). It appears in certain cases from racemic solutions or melts (spontaneous resolution) and is often quoted as one of the possible sources of optical resolution in the biological world. On the other hand, the more commonly found process of heterochiral self-recognition gives rise to a racemic supramolecular assembly of enantio pairs (204). 

The nanostructured molecular arrangements from DNA developed by Seeman may find applications as biological encapsulation and drug-delivery systems, as artificial multienzymes, or as scaffolds for the self-assembling nanoscale fabrication of technical elements. Moreover, DNA-protein conjugates may be anticipated as versatile building blocks in the fabrication of multifunctional supramolecular devices and also as highly functional-... 

The reviews collected in this book convey some of the themes recurrent in nano-colloid science self-assembly, constraction of supramolecular architecture, nanoconfmement and compartmentalization, measurement and control of interfacial forces, novel synthetic materials, and computer simulation. They also reveal the interaction of a spectrum of disciplines in which physics, chemistry, biology, and materials science intersect. Not only is the vast range of industrial and technological applications depicted, but it is also shown how this new way of thinking has generated exciting developments in fundamental science. Some of the chapters also skirt the frontiers, where there are still unanswered questions. 

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