Crystal structure of mammalian purple acid phosphatase

Structure. 1999 Jul 15;7(7):757-67. doi: 10.1016/s0969-2126(99)80100-2.


Background: Mammalian purple acid phosphatases are highly conserved binuclear metal-containing enzymes produced by osteoclasts, the cells that resorb bone. The enzyme is a target for drug design because there is strong evidence that it is involved in bone resorption.

Results: The 1.55 A resolution structure of pig purple acid phosphatase has been solved by multiple isomorphous replacement. The enzyme comprises two sandwiched beta sheets flanked by alpha-helical segments. The molecule shows internal symmetry, with the metal ions bound at the interface between the two halves.

Conclusions: Despite less than 15% sequence identity, the protein fold resembles that of the catalytic domain of plant purple acid phosphatase and some serine/threonine protein phosphatases. The active-site regions of the mammalian and plant purple acid phosphatases differ significantly, however. The internal symmetry suggests that the binuclear centre evolved as a result of the combination of mononuclear ancestors. The structure of the mammalian enzyme provides a basis for antiosteoporotic drug design.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acid Phosphatase / chemistry*
  • Acid Phosphatase / metabolism
  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Catalytic Domain
  • Crystallography, X-Ray
  • Glycoproteins / chemistry*
  • Glycoproteins / metabolism
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Sequence Homology, Amino Acid
  • Swine


  • Glycoproteins
  • purple acid phosphatase
  • Acid Phosphatase

Associated data

  • PDB/1UTE