A question that has crossed the minds of most humans is: How did we get here? As interesting a question as it may be, it is unlikely ever to generate definitive answers. It has nonetheless led to many hypotheses on the origin of life, all of which lack experimental evidence to support some of their conjectures, thereby exposing gaps in our knowledge. One significant gap is concerning the origins of molecular complexity, particularly the creation of nucleic acid and peptide polymers of a length and stability that would allow them to accumulate to a significant extent.
Jason Greenwald, Michael P. Friedmann, and Roland Riek, Swiss Federal Institute of Technology (ETH) Zurich, Switzerland, show that under mild conditions relevant to a prebiotic Earth, the simple amino acids alanine, valine, glycine, and aspartic acid condense into oligomers of 6 to 14 amino acids that spontaneously assemble into insoluble, fibrous structures.
The team used matrix-assisted laser desorption/ionization Fourier-transform ion cyclotron resonance mass spectrometry (MALDI-FT-ICR MS), circular dichroism (CD) spectroscopy, attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, and X-ray diffraction to characterize the structures and revealed them to be amyloid. Amyloids are highly ordered stable peptide aggregates that, in addition to their link to diseases such as Alzheimer’s, have been reported to have unique functional and catalytic properties.
According to the researchers, Amyloids, with their polyfunctional nature, may allow the bridging of the diverse theories on the origins of life.
- Amyloid Aggregates Arise from Amino Acid Condensations under Prebiotic Conditions,
Jason Greenwald, Michael P. Friedmann, Roland Riek,
Angew. Chem. Int. Ed. 2016.