Two different neurodegenerative diseases caused by proteins with similar structures.
Mo, H., Moore, R.C., Cohen, F.E., Westaway, D., Prusiner, S.B., Wright, P.E., Dyson, H.J.(2001) Proc Natl Acad Sci U S A 98: 2352-2357
- PubMed: 11226243 
- DOI: https://doi.org/10.1073/pnas.051627998
- Primary Citation of Related Structures:  
1I17 - PubMed Abstract: 
The downstream prion-like protein (doppel, or Dpl) is a paralog of the cellular prion protein, PrP(C). The two proteins have approximately 25% sequence identity, but seem to have distinct physiologic roles. Unlike PrP(C), Dpl does not support prion replication; instead, overexpression of Dpl in the brain seems to cause a completely different neurodegenerative disease. We report the solution structure of a fragment of recombinant mouse Dpl (residues 26-157) containing a globular domain with three helices and a small amount of beta-structure. Overall, the topology of Dpl is very similar to that of PrP(C). Significant differences include a marked kink in one of the helices in Dpl, and a different orientation of the two short beta-strands. Although the two proteins most likely arose through duplication of a single ancestral gene, the relationship is now so distant that only the structures retain similarity; the functions have diversified along with the sequence.
Organizational Affiliation: 
Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.