Origem da vida: facinho, facinho, sô -- basta adicionar água!!!

sábado, maio 08, 2010

Peptides May Hold 'Missing Link' to Life

ScienceDaily (May 7, 2010) — Emory scientists have discovered that simple peptides can organize into bi-layer membranes. The finding suggests a "missing link" between the pre-biotic Earth's chemical inventory and the organizational scaffolding essential to life.


Researchers tagged one end of peptide chains with an NMR label, and then allowed them to assemble to see if the ends would interact. The result was a bi-layer membrane with inner and outer faces and an additional, buried layer that localized functionality within the interior. (Credit: Image courtesy of Emory University)

"We've shown that peptides can form the kind of membranes needed to create long-range order," says chemistry graduate student Seth Childers, lead author of the paper recently published by the German Chemical Society's Angewandte Chemie. "What's also interesting is that these peptide membranes may have the potential to function in a complex way, like a protein."

Chemistry graduate student Yan Liang captured images of the peptides as they aggregated into molten globular structures, and self-assembled into bi-layer membranes. The results of that experiment were recently published by the Journal of the American Chemical Society.

"In order to form nuclei, which become the templates for growth, the peptides first repel water," says Liang, who is now an Emory post-doctoral fellow in neuroscience. "Once the peptides form the template, we can now see how they assemble from the outer edges."
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Many groups studying the origins of life have focused on RNA, which is believed to have pre-dated living cells. But RNA is a much more complicated molecule than a peptide. "Our studies have now shown that, if you just add water, simple peptides access both the physical properties and the long-range molecular order that is critical to the origins of chemical evolution," Childers says.
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Read more here: Science Daily

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1. W. Seth Childers, Anil K. Mehta, Rong Ni, Jeannette V. Taylor, David G. Lynn. Peptides Organized as Bilayer Membranes. Angewandte Chemie International Edition, 2010; DOI: 10.1002/anie.201000212

2. Yan Liang, David G. Lynn, Keith M. Berland. Direct Observation of Nucleation and Growth in Amyloid Self-Assembly. Journal of the American Chemical Society, 2010; 132 (18): 6306 DOI: 10.1021/ja910964c

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NOTA CAUSTICANTE DESTE BLOGGER:

A vida é de uma complexidade tal que até hoje a ciência não sabe definir o que é vida. E vem um sujeito desses [a Galera dos meninos e meninas de Darwin vai dizer que é falta de colegialidade de minha parte. Eu ia dizer otras cositas aqui, mas são impublicáveis]  dizer que para se conseguir a evolução química [seja lá o que isso signifique] basta tão-somente adicionar água! A água é um solvente universal, não é? Pelo menos foi o que aprendi em Química 101.

Fui, nem sei por que, pensando, mas a origem da vida não é assim tão facinha quanto este sujeito sugeriu: basta adicionar água. Quase morri de rir!!!