Comparison of ascorbate peroxidase amino acid sequences. A: Amino acid sequence alignment of ascorbate peroxidases (APx) from Arabidopsis thaliana (At), Selaginella moellendorffii (Sm), Physcomitrella patens (Pp) and Chlamydomonas reinhardtii (Cr). The label "H2O2" marks the H2O2-binding site, "C" the amino acids involved in formation of the catalytic site, "P" the proximal and "D" the distal cation binding site and "H" the heme binding amino acids. B: Phylogramme of APx proteins. The proteins depicted in Fig. 1A are marked in red. They are compared to all putative full-length organellar APx listed in PeroxiBase and a selection of extra-organellar APx. The tree was calculated based on the neighborhood joining algorithm. Additional in PeroxiBase predicted, but not in Fig. 1A listed APx from Arabidopsis thaliana, Physcomitrella patens and Chlamydomonas reinhardtii are labeled in green. For all PeroxiBase-data the data base IDs are presented in the labels. The numbers represent bootstrap values for the branches as calculated based on 500 bootstraps. Maximum parsimony and minimum evolution trees are shown in the additional files 1 and 2.