Scenarios for origin of functional biopolymers

Complex coacervates can be thought of as “assemblies” or “clusters” of multiply charged molecules. They can attract and concentrate other biomolecules such as RNA and proteins. During the early Earth, biomolecules having catalytic functions were likely scarce. In the image above (bottom right) you can see fluorescent RNAs (green) clustered and enriched within complex coacervates. It would have been beneficial for such molecules to be compartmentalized. Because complex coacervates do not have a membrane, biomolecules can easily accumulate inside them. We demonstrated that components of complex coacervates can facilitate in making RNA molecules in the absence of any enzymes and magnesium, an essential element required for such reactions.  Furthermore, we show that complex coacervates can concentrate RNA enzymes, increasing their concentrations- which results in activation of RNA catalysis. As such, our work shows that membraneless compartments formed by complex coacervates may have facilitated to promote both enzymatic and non-enzymatic reactions during the primordial Earth. Interestingly, there are also membraneless organelles in cytoplasm, which are formed by similar chemical interactions   

 

We recently published a paper in Nature Communications that incorporates these themes. (link) 

 

Also see-Frankel EA, Bevilacqua PC, Keating CD. Langmuir (2016)