Self-replication phases

PLP itself, however, is presumably much older than this. There are general arguments suggesting that organic cofactors and coenzymes represent biochemical fossils from very primitive stages in the history of life. In particular, the fact that several cofactors show nucleotide-like features is often used to support the occurrence of an RNA world, that is, a very early phase of biotic evolution in which RNA molecules were capable of self-replication and of a rudimentary form of metabolism. Within this hypothetical world, cofactors and coenzymes would have helped expand the chemical repertoire of catalytic RNAs. "... 

Figure 15. Orientational presentation of liberation of solid-phase information content into self-replicating biomesogenic information patterns, neglecting complex intermediate states of highly condensed information channel designs (left top to bottom) solid-phase space-partitioners Ca3[Al2Si 20 2J, Li 4MgSi4, TagCl 5 [32c] (right) replicative DNA, including water cover and counterion clouds [33 a, c, p, q].

The second phase, namely the self-organising mechanism of the molecular self-replication has been investigated by Eigen (1971) and his coworkers (Eigen Schuster, 1979) unifying the detailed results of biochemical experiments with mathematical models of chemical kinetics. Theoretical studies have initially been motivated by the test-tube experiments on RNA evolution (for an early review see Spiegelman (1971)). The molecular mechanism of RNA replication is still always being studied (Biebricher et aiy 1983). 

In the Gray-Scott model PI of this system, both reactions are considered to be irreversible. This reaction scheme is a simplification of the autocatalytic model of the glycolysis cycle (see Chapter 7). A is a feed term and B an inert product. PearsonI °l has shown that as a function of kinetic and diffusion parameters this system leads to the formation of local regions of concentration defined by sharp boundaries. These local regions take on cell-like characteristics, thus undergoing multiplication and division behavior. We discuss some of the results in detail, also because of the discussion in the next chapter on self replication and the origin of protocellular systems. As a function of feed (F) and rate parameter (fc), a state phase diagram can be constructed (see Fig. 8.5). 

Another iterative approach to generate an exponential self-replicating system combines solid-phase chemistry with chemical replication of oligonucleotides. At the start of the reciprocal version of this procedure, two complementary oligonucleotide templates are immobihzed onto a solid support. Appropriate nucleotide building blocks can then be recognized on the templates and reacted to form copies of both strands. Treatment of the duplexes with polar... 

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