Figure 1. Mature PrP and Dpl protein share common structural architectures.

(A) PrP^C and Dpl have common secondary structure elements, composed by three alpha helices (αA, αB and αC) and two beta strands (βA and βB). Both PrP^C and Dpl have N-glycosylation sites (*), disulfide bridges (S-S) and a GPI-moiety, which links the proteins to the extracellular side of the cellular membrane. PrP^C and Dpl also share a positively charged N-terminus. PrP^C contains five octapeptide repeats capable of binding copper through histidine residues (modified from [52]). (B) The topology of Dpl (PDB code: 1I17, left structure) is very similar to that of PrP^C (PDB code: 1AG2, central structure). A significant difference is that αB helix of Dpl (in green, right image) is bent and that the two beta strands are oriented differently than those in the PrP^C (in orange, right image). (C) Sequence alignment between mouse PrP^C (mPrP, residues Val¹²⁰–Arg²²⁹; SwissProt entry: P04925) and mouse Dpl (mDpl, residues Asn⁵⁵–Gly¹⁵⁵; SwissProt entry: Q9QUG3) proteins. In this tract the two proteins share 18% of sequence identity and 44% of sequence similarity. Fully conserved residues are highlighted in red, while semi-conserved are shown in blue.