Biomolecules Natural polymers Organic

In this chapter we describe the basic principles involved in the controlled production and modification of two-dimensional protein crystals. These are synthesized in nature as the outermost cell surface layer (S-layer) of prokaryotic organisms and have been successfully applied as basic building blocks in a biomolecular construction kit. Most importantly, the constituent subunits of the S-layer lattices have the capability to recrystallize into iso-porous closed monolayers in suspension, at liquid-surface interfaces, on lipid films, on liposomes, and on solid supports (e.g., silicon wafers, metals, and polymers). The self-assembled monomolecular lattices have been utilized for the immobilization of functional biomolecules in an ordered fashion and for their controlled confinement in defined areas of nanometer dimension. Thus, S-layers fulfill key requirements for the development of new supramolecular materials and enable the design of a broad spectrum of nanoscale devices, as required in molecular nanotechnology, nanobiotechnology, and biomimetics [1-3]. 

Chapters 1 through 21 cover the topics that most instructors will include in their courses, with the possible exception of Chapter 15. The remaining chapters offer a choice for the last part of the course. They include chapters on pericyclic reactions, synthesis, and polymers. The chapters on the more biochemical topics—carbohydrates, amino acids and proteins, nucleotides and nucleic acids, and other natural products— concentrate on the organic chemistry of these important biomolecules. 

If a mixture of L- and D-alanine were caused to polymerize, nearly all the polymer molecules would have different structures because their sequences of D-alanine and L-alanine monomer units would differ. To create polymers with definite structures for particular roles, there is only one recourse to build all polypeptides from one of the optical isomers so that the properties will be reproducible from molecule to molecule. Nearly all naturally occurring a-amino acids are of the L form, and most earthly organisms have no use for D-a-amino acids in making polypeptides. Terrestrial life could presumably have begun equally well using mainly D-amino acids (all biomolecules would be mirror images of their present forms). The mechanism by which the established preference was initially selected is not known. 

The low-temperature nature of the sol-gel process lends itself well to the entrapment of organic materials (dyes, polymers, redox reagents) and biomolecules (enzymes, proteins, antibodies, whole cells) which are immobilized inside an inorganic matrix. This opens up a whole new class of materials with unique properties. This rapidly growing topic has been extensively reviewed in the... 

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