Fig. 8. Proteins with the same phylogenetic profile as the originally identified mitochondrial Gsp homologues.

a Schematic domain representation of 23 proteins occurring in heteroloboseans, jakobids and malawimonads with the core T2SS subunits but not in other eukaryotes analyzed. Proteins with a functional link to the T2SS suggested by sequence homology are shown in blue, proteins representing novel paralogues within broader (super) families are shown in violet, and proteins without discernible homologues or with homologues only in prokaryotes are shown in pink. The presence of conserved protein domains or characteristic structural motifs is shown if detected in the given protein. Grey block – predicted transmembrane domain (see also Supplementary Fig. 11); “C H C H” – the presence of absolutely conserved cysteine and histidine residues (see also Supplementary Fig. 12) that may mediate binding of a prosthetic group; “HEXXH” and “EXXA” in Gcp16 indicate absolutely conserved motifs suggesting that the protein is a metallopeptidase of the gluzincin group (see text). The length of the rectangles corresponds to the relative size of the proteins. b Protein sequence alignment of Gcp12 proteins with highlighted conserved cysteine (black circles) and histidine (red circles) residues. c The expression of GoGcp12 in T. brucei with the C-terminal V5 tag (green) showed partial co-localisation with the mitochondrion (red) (representative image of three experiments is shown). Scale bar 10 µm.