Unusual space-group pseudosymmetry in crystals of human phosphopantothenoylcysteine decarboxylase

Acta Crystallogr D Biol Crystallogr. 2003 Oct;59(Pt 10):1762-6. doi: 10.1107/s0907444903016214. Epub 2003 Sep 19.


Phosphopantothenoylcysteine (PPC) decarboxylase is an essential enzyme in the biosynthesis of coenzyme A and catalyzes the decarboxylation of PPC to phosphopantetheine. Human PPC decarboxylase has been expressed in Escherichia coli, purified and crystallized. The Laue class of the diffraction data appears to be 3m, suggesting space group R32 with two monomers per asymmetric unit. However, the crystals belong to the space group R3 and the asymmetric unit contains four monomers. The structure has been solved using molecular replacement and refined to a current R factor of 29%. The crystal packing can be considered as two interlaced lattices, each consistent with space group R32 and with the corresponding twofold axes parallel to each other but separated along the threefold axis. Thus, the true space group is R3 with four monomers per asymmetric unit.

MeSH terms

  • Carboxy-Lyases / biosynthesis
  • Carboxy-Lyases / chemistry*
  • Carboxy-Lyases / genetics
  • Crystallization
  • Crystallography, X-Ray
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Humans
  • Models, Molecular
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Static Electricity


  • Recombinant Proteins
  • Carboxy-Lyases
  • Phosphopantothenoyl-cysteine decarboxylase