The role of molecular crowding in long-range metalloprotein electron transfer: Dissection into site- and scaffold-specific contributions
By Zitare, Ulises A.; Szuster, Jonathan; Scocozza, Magali F.; Espinoza-Cara, Andr
Published in Electrochimica Acta
2019
Abstract
Here we report the effect of molecular crowding on long-range protein electron transfer (ET) and disentangle the specific responses of the redox site and the protein milieu. To this end, we studied two different one-electron redox proteins that share the cupredoxin fold but differ in the metal center, T1 mononuclear blue copper and binuclear CuA, and generated chimeras with hybrid properties by incorporating different T1 centers within the CuA scaffold or by swapping loops between orthologous proteins from different organisms to perturb the CuA site. The heterogeneous ET kinetics of the different proteins was studied by protein film electrochemistry at variable electronic couplings and in the presence of two different crowding agents. The results reveal a strong frictional control of the ET reactions, which for 10