CuA-based chimeric T1 copper sites allow for independent modulation of reorganization energy and reduction potential

Abstract

Attaining rational modulation of thermodynamic and kinetic redox parameters of metalloproteins is a key milestone towards the (re)design of proteins with new or improved redox functions. Here we report that implantation of ligand loops from natural T1 proteins into the scaffold of a CuA protein leads to a series of distorted T1-like sites that allow for independent modulation of reduction potentials (E°′) and electron transfer reorganization energies (λ). On the one hand E°′ values could be fine-tuned over 120 mV without affecting λ. On the other, λ values could be modulated by more than a factor of two while affecting E°′ only by a few millivolts. These results are in sharp contrast to previous studies that used T1 cupredoxin folds, thus highlighting the importance of the protein scaffold in determining such parameters. This journal is