Extended Data Fig. 8: “Recent” evolution of a tertiary contact and phylogenetic comparisons.

a) Conservation vs. Tolerance among bacterial Form II rubiscos. As in Fig. 2c, mutational tolerance is the average fitness effect of all mutations at a given position. Here conservation is determined from an MSA of all Form II bacterial rubiscos (see methods). P-value is determined from the Spearman correlation and is thus a two-sided test. Positions 215 and 257 form a tertiary contact in R. rubrum and other Form II rubiscos and are thus more conserved than among all rubiscos. b) Alignment of 9RUB and 8RUC, R. rubrum (green) and spinach (orange) rubisco respectively. c) Rotated view and zoom of M215 and H257 from R. rubrum. The loop containing them in R. rubrum is truncated in spinach. d) Pairwise identities between rubisco sequences across Forms. Representative rubisco sequences from⁵ were compared for pairwise identity. Form I sequences were picked to have a maximum sequence identity between one another of 85% in order to sample sequences more evenly (out of fear of oversampling plant sequences). Form II and III sequences were chosen randomly.