Fig. 4.

—A novel pt-targeted paralog of the ribosomal protein L26 in eustigmatophytes. The ML tree was inferred from an alignment of 115 amino acid position using IQ-TREE v1.6.5 and the optimal substitution model selected by the program (LG + I + Γ4). Bootstrap values <75 are omitted from the figure. The tree displayed unveils the existence of a separate clade of L26-related sequences encoded by nuclear genomes of all eustigmatophytes investigated and possessing an N-terminal extension fitting the structure of a bipartite pt-targeting presequence (supplementary table S4, Supplementary Material online). This clade is clearly separated from conventional L26 proteins lacking the N-terminal targeting sequence and expected to function as components of the cytosolic ribosomes, as well as from the presumably independently evolved group of pt-targeted L26 proteins from euglenophytes. The tree was arbitrarily rooted between sequences from Archaea and eukaryotes.