Self-replication without hydrogen bonds: an exobiotic design

Life on Earth uses DNA as a central template for self-replication, genetic coding and information transmission.

However, there are no physical laws that rule out the existence of life elsewhere in space, and alternative life forms may not need DNA. When searching for exobiology, figuring out what to look for as a biosignature remains a challenge – especially if it doesn’t come from the obvious list of biological building blocks.

Evidence from chemicals recently discovered on Mars and in the Taurus Molecular Cloud 1 (TMC-1) shows that there are intriguing organic compounds outside of Earth that could provide a starting point for unconventional exobiotic designs.

Here, we present a new self-replicating system with structural similarities to recently discovered compounds on Mars and TMC-1. Instead of using the hydrogen bonding motif of DNA for reliable base pairing, our design exploits sulfur-nitrogen interactions to specifically generate unique benzothiadiazole units in a sequence.

We synthesized and studied two versions of this system, one reversible and one irreversible, and found experimental evidence of self-replication in the solvent d-chloroform. These results are part of a larger effort in our laboratory to develop a basis for a potential exobiological system using starting building blocks closely related to these cosmic compounds.

Chemistry – A European Journal ( IF 3.9 Submission Guide >) Publication date: 2024-07-03 , Self-replication without hydrogen bonds: An exobiotic design, x-mol.net

DOI:10.1002/chem.202401446
Mark R. Ams, Joseph R. McAuliffe, Raina S. Semenick, Matthias Zeller,
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Astrobiology, Astrochemistry,