Research on protocells sheds new light on the evolution of life
8 August 2011
Researchers at the University of Bristol have designed a chemical system which represents perhaps the simplest protocell model of cell formation on the early Earth. The work is described in an article published today in Nature Chemistry.
Professor Stephen Mann and colleagues in the School of Chemistry have now attacked this intriguing problem by designing a chemical system which spontaneously assembles into water-containing micro-droplets, which contain the cellular energy molecule, adenosine triphosphate (ATP), and a short polymer of the natural amino acid lysine.
The droplets form via a process known as coacervation, and unlike modern cells they are membrane-free. Intriguingly, the droplets select and sequester molecules such as iron porphyrins, which are ancient molecules essential for oxygen binding, and the environment in the interior of the droplets is amenable to other chemical processes including nanoparticle and enzymatic catalysis powered by the ATP contained within the droplets.
In essence, Professor Mann's system represents perhaps the simplest protocell model of cell formation on the early Earth, where the increasing complexity required for life is driven by chemical evolution via selective partitioning between the interior and exterior of the droplets without the need for a membrane.
“Taken together, our results suggest that peptide–nucleotide microdroplets can be considered as a new type of protocell model that could be used to develop novel bioreactors, primitive artificial cells and plausible pathways to prebiotic organization before the emergence of lipid-based compartmentalization on the early Earth,” the authors say.
‘Peptide–nucleotide microdroplets as a step towards a membrane-free protocell model’ by Shogo Koga, David S.Williams, AdamW. Perriman and Stephen Mann in Nature Chemistry