High-potential states of blue and purple copper proteins

Biochim Biophys Acta. 1998 Nov 10;1388(2):437-43. doi: 10.1016/s0167-4838(98)00205-2.

Abstract

Electrochemical measurements show that there are high-potential states of two copper proteins, Pseudomonas aeruginosa azurin and Thermus thermophilus CuA domain; these perturbed states are formed in guanidine hydrochloride (GuHCl) solution in which the proteins are still blue (azurin) and purple (CuA). In each case, the high-potential state forms reversibly. Absorption (azurin, CuA), visible circular dichroism (azurin, CuA), resonance-Raman (CuA), and EPR (CuA) spectra indicate that the structure of the oxidized copper site of each high-potential form is very similar to that of the native protein. It is proposed that GuHCl perturbs one or more H-bonds in the blue or purple copper active site, thereby allowing Cu(I) to adopt a more favorable coordination structure than that in the rigid cavity of the native protein.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Azurin / chemistry*
  • Bacterial Proteins / chemistry
  • Circular Dichroism
  • Copper / chemistry*
  • Electrochemistry
  • Electron Spin Resonance Spectroscopy
  • Electron Transport Complex IV / chemistry*
  • Guanidine / pharmacology
  • Hydrogen Bonding
  • Metalloproteins / chemistry
  • Molecular Structure
  • Oxidation-Reduction
  • Protein Denaturation
  • Protein Folding
  • Pseudomonas aeruginosa / chemistry*
  • Spectrophotometry
  • Spectrum Analysis, Raman
  • Thermus thermophilus / chemistry*

Substances

  • Bacterial Proteins
  • Metalloproteins
  • Azurin
  • Copper
  • Electron Transport Complex IV
  • Guanidine