Stabilization of Cu(I) for binding and calorimetric measurements in aqueous solution.
Conditions have been developed for the comproportionation reaction of Cu(2+) and copper metal to prepare aqueous solutions of Cu(+) that are stabilized from disproportionation by MeCN and other Cu(+)-stabilizing ligands. These solutions were then used in ITC measurements to quantify the thermodynamics of formation of a set of Cu(+) complexes (Cu(I)(MeCN)3(+), Cu(I)Me6Trien(+), Cu(I)(BCA)2(3-), Cu(I)(BCS)2(3-)), which have stabilities ranging over 15 orders of magnitude, for their use in binding and calorimetric measurements of Cu(+) interaction with proteins and other biological macromolecules. These complexes were then used to determine the stability and thermodynamics of formation of a 1 : 1 complex of Cu(+) with the biologically important tri-peptide glutathione, GSH. These results identify Me6Trien as an attractive Cu(+)-stabilizing ligand for calorimetric experiments, and suggest that caution should be used with MeCN to stabilize Cu(+) due to its potential for participating in unquantifiable ternary interactions.
Department of Chemistry, Physics and Geology, Winthrop University, Rock Hill, SC 27933, USA. grossoehmen@winthrop.edu.
Destinee K
DK
Johnson
Michael J
MJ
Stevenson
Zayed A
ZA
Almadidy
Sharon E
SE
Jenkins
Dean E
DE
Wilcox
Nicholas E
NE
Grossoehme
D000097:Acetonitriles / Q000737:chemistry; D002151:Calorimetry; D056831:Coordination Complexes / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005978:Glutathione / Q000737:chemistry; D008024:Ligands; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D000097:Acetonitriles; D056831:Coordination Complexes; D008024:Ligands; D014867:Water; D003300:Copper; D005978:Glutathione; C032159:acetonitrile