Crystal structures of wild-type and mutated cyclophilin B that causes hyperelastosis cutis in the American quarter horse

BMC Res Notes. 2012 Nov 8:5:626. doi: 10.1186/1756-0500-5-626.


Background: Hyperelastosis cutis is an inherited autosomal recessive connective tissue disorder. Affected horses are characterized by hyperextensible skin, scarring, and severe lesions along the back. The disorder is caused by a mutation in cyclophilin B.

Results: The crystal structures of both wild-type and mutated (Gly6->Arg) horse cyclophilin B are presented. The mutation neither affects the overall fold of the enzyme nor impairs the catalytic site structure. Instead, it locally rearranges the flexible N-terminal end of the polypeptide chain and also makes it more rigid.

Conclusions: Interactions of the mutated cyclophilin B with a set of endoplasmic reticulum-resident proteins must be affected.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Crystallography, X-Ray
  • Cyclophilins / chemistry*
  • Cyclophilins / genetics*
  • Horse Diseases / enzymology
  • Horse Diseases / genetics*
  • Horses
  • Models, Molecular
  • Mutation, Missense*
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Skin / enzymology
  • Skin / metabolism
  • Skin / pathology
  • Skin Diseases / enzymology
  • Skin Diseases / genetics*
  • Skin Diseases / veterinary


  • cyclophilin B
  • Cyclophilins

Associated data

  • PDB/4FRU
  • PDB/4FRV