Long distance electron transfer through the aqueous solution between redox partner proteins
Molecular dynamics simulations of redox protein partners hCc (left, orange) and pCc1 (right, green) indicate that a reduced ionic density at the volume confined between them causes an extended electric field (equipotential lines shown in the background). Heme groups are highlighted in each protein. Image credit: Alba Nin-Hill.
Lagunas A, Guerra-Castellano A, Nin-Hill A, Diaz-Moreno I, De la Rosa MA, Samitier J, Rovira C, Gorostiza P.
Nat Commun 2018 Dec; 9: 5157.
Despite the importance of electron transfer between redox proteins in photosynthesis and respiration, the inter-protein electron transfer rate between redox partner proteins has never been measured as a function of their separation in aqueous solution. Here, we use electrochemical tunneling spectroscopy to show that the current between two protein partners decays along more than 10 nm in the solution. Molecular dynamics simulations reveal a reduced ionic density and extended electric field in the volume confined between the proteins. The distance-decay factor and the calculated local barrier for electron transfer are regulated by the electrochemical potential applied to the proteins. Redox partners could use electrochemically gated, long distance electron transfer through the solution in order to conciliate high specificity with weak binding, thus keeping high turnover rates in the crowded environment of cells.
PubMed: 30514833. Doi: 10.1038/s41467-018-07499-x. Free PMC article
