Functionalization of biopolymers

Synthesis of reactive nucleic acids derivatives and their use for investigations of structure and functions of biopolymers 98UK688. 

The biological function of biopolymers such as polypeptides, proteins, nucleic acids etc. depends strongly on their ordered structure which is determined by the pattern of inter- and intramolecular interactions given by the primary structure. 

Figure 7. An optimization technique for properties and functions of biopolymers based on molecular evolution with intervention. The goal is achieved by means of selection cycles. Each cycle consists of three phases (i) amplification of initial or...

A large number of macromolecules possess a pronounced amphiphilicity in every repeat unit. Typical examples are synthetic polymers like poly(l-vinylimidazole), poly(JV-isopropylacrylamide), poly(2-ethyl acrylic acid), poly(styrene sulfonate), poly(4-vinylpyridine), methylcellulose, etc. Some of them are shown in Fig. 23. In each repeat unit of such polymers there are hydrophilic (polar) and hydrophobic (nonpolar) atomic groups, which have different affinity to water or other polar solvents. Also, many of the important biopolymers (proteins, polysaccharides, phospholipids) are typical amphiphiles. Moreover, among the synthetic polymers, polyamphiphiles are very close to biological macromolecules in nature and behavior. In principle, they may provide useful analogs of proteins and are important for modeling some fundamental properties and sophisticated functions of biopolymers such as protein folding and enzymatic activity. 

Moderate hydrogen bonds are generally formed by neutral donor and acceptor groups, such as —O—H, =N—H, or — N(H)—H and 0=, 0=C, or N=, in which the donor X is electronegative relative to hydrogen and the Y atom (the acceptor) has a lone pair of unshared electrons. These are the most common hydrogen bonds and are essential contributors to the structure and function of biopolymers. 

The Dielectric Effect of Proton Exchange with Zmtterions.— Besides structural transitions, binding or transfer reactions with small molecules or ions represent another very important class of elementary functions of biopolymers. Appreciable changes of dipole moments in such processes could also lead to chemically induced dielectric relaxation. A pertinent model binding-process was discussed eariier. An analogous typical transfer-reaction scheme can be generally written as... 

Life would have been impossible without the chirality of its molecules, which is required for the larger spectrum of biomolecules, their 3-dimensional assembly, and for the functions of biopolymers. In this balance, the unnatural, nonprotein amino acids detected in some meteorites may have played an especially significant role. 

The model compound used for the elucidation of biopolymers will also be useful to utilize the function of biopolymers for reactions in vitro. The information implanted in biopolymers is organized to match with the actions of the biopolymers in vivo. There might be some informatirxi which is useless for the action in vitro. 

One of the long-standing goals of foldamer research has been to mimic the function of biopolymers. While the focus has been on establishing the principles of folding, there have been some successes in designing shape-dependent function. For example, it was recently shown that p-peptides, peptoids, and simple polymers could capture the antimicrobial activity and selectivity of the natural host defense peptides [23-27]. As foldamer researchers develop more sophisticated stmctures, we expect many more examples. 

This book consists of 15 chapters and gives an overview on different kinds of biopolymers, their surface modification, and successful utilization for different applications. It also summarizes the developments made in the area of surface functionalization of biopolymers. A number of critical issues and suggestions for future work are discussed in a number of chapters, underscoring the roles of researchers for the efficient development of new techniques for surface modification through value addition to enhance their use. 

As we noted in the preceding section, in spite of the microscopic dimensions of molecular machines, each macromolecular device is large enough to be considered as a statistical system. Thus, the behavior of any individual molecular machine can be described in terms of statistical thermodynamics. On the other hand, there are certain mechanical features in the behavior of molecular machines. The reader can find a lot of theoretical and experimental data concerning various aspects of the structure and functioning of biopolymers in plenty of excellent monographs, and in original and review-... 

E.R. Henry, J. Hofreichter, and W. Eaton (1987), In Structure, Dynamics and Function of Biopolymers, Springer Series in Biophysics, vol. 1, Springer-Verlag, New York, pp. 20-24. 

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