Fig. 5. Molecular mechanism for the preservation of phylogenetic signals in fossils (based on data in Figs. 1A, 2A, 3, and 4, A and C to E).

The reactive amino acids lysine, arginine, histidine, cysteine, and the protein N terminus (labeled in red) form characteristic fossilization products under suitable conditions. Brown circles indicate extensions of the geopolymer. Nu, nucleophile; Δ, thermal energy input.