The structure of plastocyanin from the cyanobacterium Phormidium laminosum

Acta Crystallogr D Biol Crystallogr. 1999 Feb;55(Pt 2):414-21. doi: 10.1107/s0907444998012074.


The crystal structure of the 'blue' copper protein plastocyanin from the cyanobacterium Phormidium laminosum has been solved and refined using 2.8 A X--ray data. P. laminosum plastocyanin crystallizes in space group P43212 with unit-cell dimensions a = 86.57, c = 91.47 A and with three protein molecules per asymmetric unit. The final residual R is 19.9%. The structure was solved using molecular replacement with a search model based on the crystal structure of a close homologue, Anabaena variabilis plastocyanin (66% sequence identity). The molecule of P. laminosum plastocyanin has 105 amino-acid residues. The single Cu atom is coordinated by the same residues - two histidines, a cysteine and a methionine - as in other plastocyanins. In the crystal structure, the three molecules of the asymmetric unit are related by a non-crystallographic threefold axis. A Zn atom lies between each pair of neighbouring molecules in this ensemble, being coordinated by a surface histidine residue of one molecule and by two aspartates of the other.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Crystallography, X-Ray
  • Cyanobacteria / chemistry*
  • Magnetic Resonance Spectroscopy
  • Molecular Sequence Data
  • Plastocyanin / chemistry*
  • Protein Conformation
  • Sequence Homology, Amino Acid
  • Zinc / chemistry


  • Plastocyanin
  • Zinc

Associated data

  • PDB/1BAW