Prebiotic Roles of Formaldehyde as an Activating Agent and a Building Block in Solid-State Peptide Modification

Signal transduction
by gaseous small molecules is an essential
process in modern living systems, where the gasotransmitters relay
cellular signals to bio(macro)molecules through covalent bond formation.
However, the origin or a primordial version of such signaling events
in abiotic worlds has been poorly understood to date. Through examination
of chemical reactivities between formaldehyde and cyclic dipeptide/diketopiperazine
derivatives in prebiotically relevant solid-state environments, this
study demonstrates that the gaseous small molecule may serve not only
as a mere building block for the abiotic construction of biomolecules
but also as an activating agent that transforms the inert peptide
into reactive, prebiotically important chemical species. In addition,
superiority of solid-state reactions or mechanochemistry to solution-based
reaction conditions described in this article may be an indication
of potential significance of the mechanical force-induced chemistry
for chemical evolution, in particular for abiotic emergence of polypeptides.