Proteins chemical evolution

This phrase is taken from a letter written by Charles Darwin (1871) that contains vague references to chemical evolution ... if we could conceive in some warm, little pond with all sorts of ammonia and phosphoric salts, light, heat, electricity etc. present that a proteine compound was chemically formed... . 

The conclusion is that membranous vesicles readily form a variety of amphiphilic molecules that would have been available in the early Earth environment, along with hundreds of other organic species. It is likely that during the chemical evolution leading to the first catalytic and replicating molecules, the ancestors of today s proteins and nucleic acids, membranous vesicles were available in the prebiotic environment, and ready to provide a home for the first forms of cellular life. 

The origin of life probably occurred in three phases (fig. 1.23) (1) The earliest phase was a period of chemical evolution during which the compounds needed for the nu-cleation of life must have been formed. These compounds include the most important class of biological macromolecules, the nucleic acids. In this phase of evolution, the synthesis of nucleic acids was noninstructed. (2) As soon as some nucleic acids were present, physical forces between them must have led to an instructed synthesis, in which the already formed molecules served as templates for the synthesis of new polymers. It seems likely that feedback loops selected out certain nucleic acids for preferential synthesis. At some point during this period of instructed synthesis more nucleic acids and possibly protein macromolecules were formed. The products of this phase of mo-... 

The dynamic process is akin to the error checking mechanisms employed in protein synthesis each reaction is reversible until the correct product has formed. In any evolutionary chemical system it is important to ensure copying fidelity and the success of dynamic combinatorial libraries indicates that concepts associate with supramolecular chemistry can be valuable in advancing chemical evolution. 

Feng DF, Cho G, Doolittle RF (1997) Determining divergence times with a protein clock update and reevaluation. Proc Nat Acad Sci USA 94 13028-13033 Ferrari G, Cultrera R (1961) Photochemical synthesis of amino-acids and a new transamination process by transfer of free amino-radicals. Nature 190 326-328 Ferris JP, Chen CT (1975) Chemical evolution. XXVI. Photochemistry of methane, nitrogen and water mixtures as... 

It is unknown when and how cooperation with amino acids, peptides, and proteins started to evolve into an RNA-protein world. However, there is an upper size limit of RNAs, which is due to a threshold error of RNA replication. The heart of the core necessary to launch the process of chemical evolution towards the RNA world must have consisted of a number of pathways for the synthesis of organic molecules from CO2, N2, and H2. Additional pathways for the synthesis of amino acids, ribose, purines, pyrimidines, coenzymes, and lipids likely combined into this core. Overall, the number of pathways required to generate nucleotides is relatively small. Pyruvate, ammonia, carbon dioxide, ATP, and glyoxalate suffice to synthesize virtually the compounds required for metabolic cycles. It seems likely that once the RNA world existed that thereafter an RNA-Peptide world developed. Details are on the following website http //www.sciencedirect.com - Cell, Volumel36, Issue 4, page 599, and a description follow below. 

Chessari, S. Thomas, R. Polticelli, F. Luisi, P. L., The production of de novo folded proteins by a stepwise chain elongation A model for prebiotic chemical evolution of macromolecular sequences. Chemistry Biodiversity 2006, 5, 1202-1210. 

The nature of the Ngose reaction is described with respect to electron donation, energy requirement, and reduction characteristics, with particular analysis of the seven classes of substrates reducible by N20se, a complex of a Mo-Fe and Fe protein. Chemical and physical characteristics of Fe protein and crystalline Mo-Fe protein are summarized. The two-site mechanism of electron activation and substrate complexation is further developed. Reduction may occur at a biological dinuclear site of Mo and Fe in which N2 is reduced to NH3 via enzyme-bound diimide and hydrazine. Unsolved problems of electron donors, ATP function, H2 evolution and electron donation, substrate reduction, N20se characteristics and mechanism, and metal roles are tabulated, Potential utilities of N2 fixation research include in-creased protein production and new chemistry of nitrogen. 

Friebele E., Shimoyama A., Hare P.E. and Pormamperuma C (1980) Adsorption of protein and nonprotein amino acids on a clay minerals a possible role of selection on chemical evolution, J. Mol. Evol. 16, 269-278. 

Living systems have existed for more than a billion (10 ) years. ET reactions may have been of importance from the early beginning, since they are possible in proteins at a quite large distance ( 15 A) and hence there are no serious restrictions due to diffusion limitations for reactants and products. Efficient ET and PT systems must have developed spontaneously at an early stage of a chemical evolution (the prebiotic evolution), which preceded the biological evolution. 

Nature created the first polymers and, through chemical evolution, such complex and important macromolecules as proteins, DNA, and polysaccharides. These were pivotal in the development of increasingly multifaceted life-forms, including Homo sapiens, who, as this species evolved, made better and better use of such polymeric materials as pitch, woolen and linen fabrics, and leather. Pre-Columbian Native Americans used natural rubber, or cachucha, to waterproof fabrics, as did Scottish chemist Charles Macintosh in nineteenth century Britain. 

In fact this line of investigation, via direct chemical experiments was almost completely abandoned, and in the late 60 s it was proposed that RNA could be a possible precursor and this was termed the RNA-world [40j. RNA would be both the information carrier and the catalyst, and a fair amount of research, including the discovery of ribozymes and enzymes made of RNA provided a possible route to the last ancestor. Despite these advances, however, the fundamental question still remains What were the chemical steps that allowed the emergence of chemical complexity that could eventually lead to the onset of life, with or without the RNA world Implicit within this question are further questions such as - how was DNA, with four based pairs, selected as a information carrier, why are only 20 amino acids utilised by proteins and what mechanism lead to the chiral world Was there chemical evolution before bio-chemical evolution Was the origin of life inorganic ... 

Life, with its paired abilities to mutate and to pass those mutations on to subsequent generations, promoted our planet s second stage of chemical evolution and inexorably increased the variety and modified the distribution of chemical substances in Earth s near-surface enviromnent. The innovation of catalytic proteins and polynucleotides, in particular, altered the chemical landscape of our planet. Consequently, for at least three billion years microbial activities have altered the chemistries of Earth s atmosphere and oceans, thus driving the co-evolution of the geo- and biospheres. Atmospheric oxygenation, the innovation of biomineralized skeletons, and the colonization of terrestrial habitats all expanded the influence of life on Earth s surface chemistry. 

On the Prospect of Templating and the Chemical Evolution of Protein Motifs... 

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