Electrostatic Regulation of Blue Copper Sites

<div> <p>In the last 50 years, the blue copper proteins became central targets of investigation. Extensive experiments focused on the first- and second-coordination spheres of Cu to probe the effect of local perturbations on its properties. We found that local electric fields, generated by charged residues evolutionarily placed throughout the protein edifice, constitute an additional significant factor regulating blue copper proteins. These fields are not random, but exhibit a highly specific directionality, negative with respect to Cu-S_Cys and Cu-S_Met in the Cu first shell. The field magnitude contributes to fine-tuning of the geometric and electronic properties of Cu sites in individual blue copper proteins. Specifically, the local electric fields evidently control the Cu-S_Met bond distance, Cu(II)-S_Cys bond covalency, and the energies of the frontier molecular orbitals, which, in turn, govern the Cu(II/I) reduction potential and the relative absorption intensities at 450 nm and 600 nm.</p> </div> <br>

Electrostatic Regulation of Blue Copper Sites

<div> <p>In the last 50 years, the blue copper proteins became central targets of investigation. Extensive experiments focused on the first- and second-coordination spheres of Cu to probe the effect of local perturbations on its properties. We found that local electric fields, generated by charged residues evolutionarily placed throughout the protein edifice, constitute an additional significant factor regulating blue copper proteins. These fields are not random, but exhibit a highly specific directionality, negative with respect to Cu-S_Cys and Cu-S_Met in the Cu first shell. The field magnitude contributes to fine-tuning of the geometric and electronic properties of Cu sites in individual blue copper proteins. Specifically, the local electric fields evidently control the Cu-S_Met bond distance, Cu(II)-S_Cys bond covalency, and the energies of the frontier molecular orbitals, which, in turn, govern the Cu(II/I) reduction potential and the relative absorption intensities at 450 nm and 600 nm.</p> </div> <br>

The Role of Metal Ions in the Electron Transport through Azurin-Based Junctions

We studied the coherent electron transport through metal–protein–metal junctions based on a blue copper azurin, in which the copper ion was replaced by three different metal ions (Co, Ni and Zn). Our results show that neither the protein structure nor the transmission at the Fermi level change significantly upon metal replacement. The discrepancy with previous experimental observations suggests that the transport mechanism taking place in these types of junctions is probably not fully coherent.

Electrostatic Regulation of Blue Copper Sites

In the last 50 years, the blue copper proteins became central targets of investigation. Extensive experiments focused on the Cu coordination to probe the effect of local perturbations on its...