A vocabulary of ancient peptides at the origin of folded proteins
Vikram Alva, Johannes Söding, Andrei N LupasCorresponding Author
Published December 14, 2015
Cite as eLife 2015;10.7554/eLife.09410
The seemingly limitless diversity of proteins in nature arose from only a few thousand domain prototypes, but the origin of these themselves has remained unclear. We are pursuing the hypothesis that they arose by fusion and accretion from an ancestral set of peptides active as co-factors in RNA-dependent replication and catalysis. Should this be true, contemporary domains may still contain vestiges of such peptides, which could be reconstructed by a comparative approach in the same way in which ancient vocabularies have been reconstructed by the comparative study of modern languages. To test this, we compared domains representative of known folds and identified 40 fragments whose similarity is indicative of common descent, yet which occur in domains currently not thought to be homologous. These fragments are widespread in the most ancient folds and enriched for iron-sulfur- and nucleic acid-binding. We propose that they represent the observable remnants of a primordial RNA-peptide world.
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NOTA DESTE BLOGGER:
Os pesquisadores examinaram proteínas existentes em criaturas vivas atuais, e inferiram uma história evolucionária a partir delas na pressuposição de que elas evoluíram de formas mais simples.