A origem da vida na edição tópica da revista Chemistry & Biodiversity

terça-feira, maio 29, 2007

A revista Chemistry & Biodiversity Vol. 4, Edição 4, publicada online em 19 de abril de 2007 pela Wiley-VCH cobre o tópico da química que deu origem à vida. São 3 artigos editados por Piet Herdewijn e M. Volkan Kisakuerek.

Você pode baixar estes artigos gratuitamente:

Christian de Duve: Chemistry and Selection

Chemistry and Selection
Christian de Duve 1 2
1Christian de Duve Institute of Cellular Pathology, Brussels
2The Rockefeller University, New York
email: Christian de Duve deduve@icp.ucl.ac.be deduve@mail.rockefeller.edu

Origin of life • Prebiotic chemistry • Selective optimization • Extraterrestrial life
Life is the product of chemistry, which obeys deterministic laws, and of natural selection, which operates on variants offered to it by chance, but may, in a number of cases, have been provided with a sufficiently extensive array of variants to be optimizing. Thus, the origin and evolution of life have been largely shaped by the contingency of environmental conditions. The possibility remaining open for consideration is that certain critical conditions are sufficiently reproducible for life to arise and even to evolve into conscious, intelligent beings elsewhere in the universe.

Received: 19 February 2007
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Albert Eschenmoser: On a Hypothetical Generation Relationship between HCN and Constituents of the reductive Citric Acid Cycle

Research Article
On a Hypothetical Generational Relationship between HCN and Constituents of the Reductive Citric Acid Cycle
Albert Eschenmoser 1 2
1Laboratory of Organic Chemistry, Swiss Federal Institute of Technology, Hönggerberg HCI H309, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich
2The Skaggs Institute for Chemical Biology at The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
email: Albert Eschenmoser eschenmoser@org.chem.ethz.ch
See also the preceeding paper [1].

Prebiotic chemistry • Autocatalytic cycles • Citric acid cycle • HCN-Tetramer • Fumaric acid, dihydroxy-

Encouraged by observations made on the course of reactions the HCN-tetramer can undergo with acetaldehyde, I delineate a constitutional and potentially generational relationship between HCN and those constituents of the reductive citric acid cycle that are direct precursors of amino acids in contemporary metabolism. In this context, the robustness postulate of classical prebiotic chemistry is questioned, and, by an analysis of the (hypothetical) reaction-tree of a stepwise hydrolysis of the HCN-tetramer, it is shown how such a non-robust chemical reaction platform could harbor the potential for the emergence of autocatalytic cycles. It is concluded that the chemistry of HCN should be revisited by focussing on its non-robust parts in order to demonstrate its full potential as one of the possible roots of prebiotic self-organizing chemical processes.
Received: 30 January 2007

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Guenter Waechtershaeuser: On the Chemistry and Evolution of the Pioneer Organism

On the Chemistry and Evolution of the Pioneer Organism
Günter Wächtershäuser 1 2
1Weinstrasse 8, D-80333 Munich
2209 Mill Race Dr., Chapel Hill, N.C. 27514, USA
email: Günter Wächtershäuser gwmunich@yahoo.com

Prebiotic chemistry • Chemo-autotrophic origin • Volcanic origin • Ligand-accelerated autocatalysis • Peptide cycle • Lipophilization • Surface metabolism • Surface lipophilization • Enzymatization • Metabolism • Iron-sulfur world

The theory of a chemo-autotrophic origin of life in a volcanic Iron-Sulfur World postulates the emergence of a pioneer organism within a flow of volcanic exhalations. The pioneer organism is characterized by a composite structure with an inorganic substructure and an organic superstructure. Within the surfaces of the inorganic substructure, iron, cobalt, nickel, and other transition-metal centers with sulfido, carbonyl, cyano, and other ligands are catalytically active, and promote the growth of the organic superstructure through carbon fixation, driven by the reducing potential of the volcanic exhalations. This pioneer organism is reproductive by an autocatalytic feedback effect, whereby some organic products serve as ligands for activating the catalytic metal centres whence they arise. This unitary structure-function relationship of the pioneer organism constitutes the Anlage for two major strands of evolution: enzymatization and cellularization, whereby the upward evolution of life by increase of molecular complexity is grounded ultimately in the transition metal-catalyzed, synthetic redox chemistry of the pioneer organism.

Received: 28 November 2006
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For more information, click http://www.interscience.wiley.com/journal/chembiodiv


Eu ainda não li os artigos, mas pelo status das pesquisas sobre a origem química da vida, penso que os autores não trarão muita novidade, mas tão-somente muito mais especulação. Bota especulação nisso que eu chamo carinhosamente de correr atrás do vento!