A team led by scientists at the University of Wisconsin-Madison has written a “cookbook” with hundreds of recipes that have the potential to give rise to life.

“The origin of life really is a something-from-nothing process,” says Betül Kaçar, a NASA-supported astrobiologist and UW–Madison professor of bacteriology. “But that something can’t happen just once. Life comes down to chemistry and conditions that can generate a self-reproducing pattern of reactions.”

Autocatalytic reactions

Chemical reactions that produce molecules that encourage the same reaction to happen again and again are called “autocatalytic reactions.” In a new study published in the Journal of the American Chemical Society, Zhen Peng, a postdoctoral researcher in the Kaçar laboratory, and collaborators compiled 270 combinations of molecules. These involve atoms from all groups and series across the periodic table that have the potential for sustained autocatalysis.

Comproportionation reactions

But to be autocatalytic, the outcome of the reaction also needs to provide starting materials for the reaction to occur again, allowing the output to become a new input.

The researchers focused their search on “comproportionation reactions,” where two compounds that include the same element (but with different numbers of electrons, or reactive states) combine to create a new compound in which the element is in the middle of the starting reactive states.

Comproportionation reactions result in multiple copies of some of the molecules involved, providing materials for the next steps in autocatalysis.

“We will never definitively know what exactly happened on this planet to generate life,” Kaçar says. “But, in a test tube, we can create multiple planetary conditions to understand how the dynamics to sustain life can evolve in the first place.”

Kaçar also leads a NASA-supported consortium called MUSE (Metal Utilization & Selection Across Eons).

Citation: Zhen Peng, Zachary R. Adam, Albert C. Fahrenbach, and Betül Kaçar. 18-Sep-2023. Assessment of Stoichiometric Autocatalysis across Element Groups. Journal of the American Chemical Society. DOI: 10.1021/jacs.3c07041 (open access)

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