Solvent-slaved protein motions accompany proton coupled electron transfer reactions catalysed by copper nitrite reductase.

Through the use of time-resolved pH-jump spectroscopy, we demonstrate how proton transfer is coupled to inter-copper electron transfer in a copper nitrite reductase (CuNiR). Combined use of electron paramagnetic resonance spectroscopy with solvent viscosity- and pressure-dependence pH-jump stopped-flow spectroscopy is used to show that solvent-slaved protein motions are linked to this proton coupled electron transfer step in CuNiR.