Room temperature high-resolution X-ray spectroscopy of electrochemically-controlled redox metalloproteins at intense beamlines

This project addresses key challenges in X-ray absorption spectroscopy studies of metal- containing proteins, namely how to control and protect against photoreduction and X-ray damage and how to generate protein samples in well-defined oxidation states. These questions are highly relevant on beamlines like I20, where the high intensity allows study of low protein concentrations (typical for biological studies) but in turn is more likely to induce damage to the protein. Exploiting expertise of Vincent and Ash in Oxford on electrochemical control of metalloproteins, we explore the applicability of a pulsed solution electrochemical flow approach, demonstrated by Best, to protect proteins during room temperature solution measurements of defined redox states. We will set up this approach on the I20 beamline and aim to generate data on a range of metalloprotein sites which will serve as models for understanding XAS of more complex enzymes.
This will include electron transfer proteins with haem and non-haem iron sites, copper and nickel sites and an iron-sulphur cluster. We then extend the study to a direct electrochemical approach in which the protein of interest is immobilised on a carbon electrode and exchanges electrons directly, enabling fast catalytic oxidation and reduction reactions in an enzyme to be controlled in situ during XAS measurement.
Research will be carried out 50% at Diamond Light Source which is the UK’s national synchrotron science facility, located at the Harwell Science and Innovation Campus in Oxfordshire. The remaining 50% research will be conducted in the Department of Chemistry at the University of Oxford. The Science Transit shuttle provides quick and convenient travel between the University of Oxford Science Area and Harwell Campus.