Natural products basic principles

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]. 

Natural product o-methylhalfordinol 117 is a basic principle of the oxa-zole alkaloids of Halfordia scleroxyla and Aegle marmelos. Annuloline 119, a blue fluorescent pigment, has been isolated from the roots of rye stalk Lolium multifiorum. The total synthesis of 2,5-disubstituted oxazole alkaloids o-methylhalfordinol and annuloline is based on the aza-Wittig reaction (Scheme 48). Thus 4-methoxyphenacylazide 115, triphenylphos-... 

A preliminary chapter is used to outline the main building blocks and the basic construction mechanisms employed in the biosynthesis of natural products. Many of these fundamental principles... 

However, even the complete understanding of these areas will not suffice to reap the full benefits embedded in the macromolecular nature of polymeric materials, which are inherent in the naturally occurring and synthetic polymeric building blocks. For that, a priori quantitative prediction of product properties, made of yet nonexistent chains or combinations of chains of different monomeric building blocks from basic principles, requiring information of only the macromolecular structure and processing conditions, is needed. 

There are a number of reviews of the application of various forms of LC-MS to the detection and identification and quantitation of specific analytes, whether they be natural products, synthetic drug leads, or metabolites. For example, Korfmacher [ 1 ] provides a good general introduction to LC-MS by describing its basic principles and how it facilitates new drug discovery. Prasain et ai. [2] have reviewed mass... 

MD-HPLC can be applied to the purification of a particular natural product or comprehensive fractionation of complex natural product mixtures.60 Figure 2 illustrated an example where such approaches have been employed. The two applications have some similarities in terms of basic separation science principles however, they have fundamental differences in system design, optimization, and operation. 

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