Fig. 3

The heterodimeric structure of Campsomeris COXII. a Western blot analysis of C. p. fossulana COXIIA and COXIIB polypeptides. The deduced position of the COXII band of Scolia, corresponding to that of other bilaterian animals with the exception of Campsomeris, is indicated by red arrowheads. b Tertiary structures of C. p. fossulana and S. bicincta COXII polypeptides, modelled in I-TASSER using crystal structures of bovine, Paracoccus denitrificans and Rhodobacter sphaeroides COXII (PDB: 1oczB, 3hb3B and 1m56B, respectively) as templates. The structural similarity between split COXII of C. p. fossulana and intact COXII of S. bicincta is shown in the superimposition panel. The central part of COXII of Scolia (and other pancrustaceans), which is missing in C. p. fossulana COXIIA and COXIIB, is depicted in blue. c Schematic alignment of COXII polypeptides and some of the regions proposed to be involved in COXII heterodimer reassembly. Terminal domains that are likely engaged in electrostatic interactions are shown in blue and marked “-“and “+”, respectively. The COXII/CytC interface is defined as in Schmidt et al. [49]