Self living systems

The unique power of synthesis is the ability to create new molecules and materials with valuable properties. This capacity can be used to interact with the natural world, as in the treatment of disease or the production of food, but it can also produce compounds and materials beyond the capacity of living systems. Our present world uses vast amounts of synthetic polymers, mainly derived from petroleum by synthesis. The development of nanotechnology, which envisions the application of properties at the molecular level to catalysis, energy transfer, and information management has focused attention on multimolecular arrays and systems capable of self-assembly. We can expect that in the future synthesis will bring into existence new substances with unique properties that will have impacts as profound as those resulting from syntheses of therapeutics and polymeric materials. 

According to Stuart Kauffman, self-organisation processes initiate a trend which leads to more complex states of the system. In living systems, there are two forces which determine order (Kauffman, 1995) ... 

Living cells are open self-sustained systems that continuously exchange energy and matter with their outside world, allowing them to maintain internal order and to synthesize the building blocks that are necessary for survival and growth [1]. 

During the last two decades, chemists have become increasingly focused on how molecules interact, i.e. on supramolecular chemistry. Dynamic intermolecular processes provide opportunities for incorporation of control, adaptation and function in man-made materials, as observed in living systems. In biology, these processes are tightly controlled by the catalytic action of enzymes. In this chapter, we focus on enzymatically controlled supramolecular polymerisation, whereby self-recognising molecular building blocks assemble to form extended onedimensional (ID) structures, or supramolecular polymers, with unique adaptive features. 

The notion of imparting its own rules draws an equivalence between biological autonomy and auto referentiality (Varela et al, 1991 Varela, 2000). In turn, auto-referentiality is related to the concept of operational closure. This is a process of circular and reflexive interdependency, whose primary effect is its own production. Operational closure must not be viewed as a lack of contact with the environment -as already stressed, any living system must be seen as an open system. The relation between autopoiesis, autonomy, and self referentiality is treated in the specialized literature, see for example Marks-Tarlow et al. (2001) and Weber (2002). 

In conclusion, returning to autopoiesis, each living system is a complex of circular interachons with its own environment, and this ensemble can be viewed as a continuous flow of mutual and coherent changes that have the aim of maintaining the equilibrium of self-idenhty. It seems clear from these considerations that for... 

Zampieri, G. G., Jackie, H., and Luisi, P. L. (1986). Determination of the structural parameters of reverse micelles after uptake of proteins. J. Phys. Chem., 90, 1849. Zeleny, M. (1977). Self-organization of living systems formal model of autopoiesis. Int. J. Gen. Sysl, 4, 13-28. 

There are two fundamental conditions for life. First, the living entity must be able to self-replicate (a topic considered in Part III) second, the organism must be able to catalyze chemical reactions efficiently and selectively. The central importance of catalysis may surprise some beginning students of biochemistry, but it is easy to demonstrate. As described in Chapter 1, living systems make use of energy from the environment. Many of us, for example, consume substantial amounts of sucrose—common table sugar—as a kind of fuel, whether in the form of sweetened foods and drinks or as sugar itself. The conversion of sucrose to C02 and... 

In addition to self-assembly of protein structures, in living systems the complex maneuvers needed to achieve properly folded tertiary structures are facilitated by the function of a pre-existing protein machinery, of which, ihe molecular chaperones are an illustrative example. Chaperones are proteins that bind to and stabilize an otherwise unstable conformer of another protein, and by controlled binding and release, facilitate its correct fate in vivo. Molecular chaperones may be said to be the natural... 

Numerous biological supramolecular structures result from self-assembly and living systems offer the ultimate in self-organization [9.4-9.8]. They provide illus-... 

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