Peptide-nucleotide microdroplets as a step towards a membrane-free protocell model

Nat Chem. 2011 Aug 7;3(9):720-4. doi: 10.1038/nchem.1110.

Abstract

Although phospholipid bilayers are ubiquitous in modern cells, their impermeability, lack of dynamic properties, and synthetic complexity are difficult to reconcile with plausible pathways of proto-metabolism, growth and division. Here, we present an alternative membrane-free model, which demonstrates that low-molecular-weight mononucleotides and simple cationic peptides spontaneously accumulate in water into microdroplets that are stable to changes in temperature and salt concentration, undergo pH-induced cycles of growth and decay, and promote α-helical peptide secondary structure. Moreover, the microdroplets selectively sequester porphyrins, inorganic nanoparticles and enzymes to generate supramolecular stacked arrays of light-harvesting molecules, nanoparticle-mediated oxidase activity, and enhanced rates of glucose phosphorylation, respectively. 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Artificial Cells / chemistry*
  • Catalysis
  • Nanoparticles / chemistry
  • Nucleotides / chemistry*
  • Peptides / chemistry*

Substances

  • Nucleotides
  • Peptides