Figure 3. Tsf1 orthologs are predicted to bind iron.

Sequences from each insect transferrin group were aligned with mammalian transferrin sequences to identify positions of putative iron-binding and putative carbonate-binding residues. The residues in these positions are shown. Insect transferrin lobes that are known to bind iron are boxed in orange. Species abbreviations are the same as those used for Figure 2. Human serum transferrin residues are labeled HsTf. Acyrthosiphon pisum has two Tsf2 orthologs, indicated by Ap5 and Ap9 (accession numbers XP_016660805 and XP_001947699). All of the Tsf1 orthologs are predicted to bind to one or two ferric ions, whereas only some of the Tsf2 orthologs and none of the Tsf3 and Tsf4 orthologs are predicted to bind iron.