Fig. 5

Cys residue enrichment of derived COXII polypeptides. a Correlation between split or enlargement of COXII and Cys content of the COXII domain exposed to the mitochondrial intermembrane space, equivalent to COXIIB. Data for Campsomeris species (p. fossulana (3) and sp. HA10513 (5)), and S. bicincta (26) are plotted in red and black, respectively. Split or enlarged polypeptides encoded by mtDNA contained an average of two-fold or more Cys residues than unmodified COXII polypeptides (Mann-Whitney U-test: P = 0.001). A complete list of genera and the taxonomy of analyzed organisms are shown in (Additional file 1: Table S1). b The distribution of Cys residues (green marks) along the COXII intermembrane space domain (blue or black (Scolia)) homologous to Campsomeris COXIIB (red)