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Scientists Discover New Chemistry That May Help Explain Origins of Cellular Life

An anonymous reader quotes a report from Phys.Org: Before life began on Earth, the environment likely contained a massive number of chemicals that reacted with each other more or less randomly, and it is unclear how the complexity of cells could have emerged from such chemical chaos. Now, a team led by Tony Z. Jia at the Tokyo Institute of Technology and Kuhan Chandru of the National University of Malaysia has shown that simple a-hydroxy acids, like glycolic and lactic acid, spontaneously polymerize and self-assemble into polyester microdroplets when dried at moderate temperatures followed by rehydration. This could be what happened along primitive beaches and river banks, or in drying puddles. These form a new type of cell-like compartment that can trap and concentrate biomolecules like nucleic acids and proteins. These droplets, unlike most modern cells, are able to merge and reform easily, and thus could have hosted versatile early genetic and metabolic systems potentially critical for the origins of life.

Previous work conducted at ELSI showed that moderate temperature drying of the simple organic compounds known as alpha-hydroxy acids, which are found in meteorites and many simulations of prebiological chemistry, spontaneously polymerizes them into mixtures of long polyesters. Building on this work, Jia and colleagues took the next step and examined these reactions under the microscope, and found that these mixed polyester systems form a gel phase and spontaneously self-assemble when rewetted to form simple cell-like structures. […] Jia and colleagues are not certain these structures are the direct ancestors of cells, but they think it is possible such droplets could have enabled the assembly of protocells on Earth. The new compartmentalization system they have found is extremely simple, they note, and could form easily in primitive environments throughout the universe. “We have this new experimental system we can now play with, so we can start to study phenomena like evolution and evolvability of these droplets. The possible combinations of structures or functions these droplets might have are almost endless. If the physical rules that govern the formation of droplets are fairly universal in nature, then we hope to study similar systems to discover whether they also can form microdroplets with novel properties,” adds Jia.

The study has been published in the journal PNAS.


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