JBIC Journal of Biological Inorganic Chemistry

, Volume 5, Issue 5, pp 551–559 | Cite as

Copper coordination in blue proteins

  • Harry B. Gray
  • Bo G. Malmström
  • R.J.P. Williams
Original Article

Abstract.

The spectroscopic and electrochemical properties of blue copper proteins are strikingly different from those of inorganic copper complexes in aqueous solution. Over three decades ago this unusual behavior was ascribed to constrained coordination in the folded protein; consistent with this view, crystal structure determinations of blue proteins have demonstrated that the ligand positions are essentially unchanged on reduction as well as in the apoprotein. Blue copper reduction potentials are tuned to match the particular function of a given protein by exclusion of water from the metal site and strict control of the positions of axial ligands in the folded structure. Extensive experimental work has established that the reorganization energy of a prototypal protein, Pseudomonas aeruginosa azurin, is ~0.7 eV, a value that is much lower than those of inorganic copper complexes in aqueous solution. The lowered reorganization energy in the protein, which is attributable to constrained coordination, is critically important for function, since the driving forces for electron transfer often are low (~0.1 eV) between blue copper centers and distant (>10 Å) donors and acceptors.

Copper protein Constrained coordination Reduction potential Reorganization energy 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© SBIC 2000

Authors and Affiliations

  • Harry B. Gray
    • 1
  • Bo G. Malmström
  • R.J.P. Williams
    • 2
  1. 1.California Institute of Technology, Beckman Institute 139-74, Pasadena, CA 91125, USA
  2. 2.University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford OX1 3QR, UK, Tel.: +44-1865-272621, Fax: +44-1865-272690

Personalised recommendations