Shining light on metalloenzyme catalysis: photochemistry coupled with electrochemistry as a mechanistic tool

The activation and redox chemistry of small molecules such as CO, CO2, H2, formate, O2, NO, N2, and NH3 by metalloenzymes play important roles in vital processes. These include the global carbon and nitrogen cycles and, in cellular environments, the production of energy or low-potential reducing equivalents (for example certain bacteria are capable of using CO2 as their sole carbon source, and H2 as their sole energy source). Despite the current urgent need for sustainable fuels and ‘green’ routes to chemical synthesis, detailed mechanistic understanding of how small molecule activation reactions are carried out in nature is often lacking. In part this is due to the high turnover frequencies achieved by the metalloenzymes which carry out these reactions, such as carbon monoxide dehydrogenase (CO2/CO, >2000 s 1), formate dehydrogenase (CO2/HCOO-, >112 s-1), and hydrogenase (H+/H2, >9000 s-1). New experimental tools are therefore required, capable of probing reactivity on fast, sub-turnover frequency timescales (ca. pico- to milli- second).

Electrochemistry provides convenient control over the oxidation state of metalloenzymes and makes it possible to regulate enzymatic turnover. However, electrochemistry is most commonly applied to studies of steady-state kinetics, and is most suited to characterisation of long-lived catalytic intermediates. In contrast, photochemical triggers are widely used for sub-turnover mechanistic studies, offering valuable insight if catalysis can be initiated by light without triggering unwanted photochemical side reactions.

During this project we will develop a combined photobioelectrochemical methodology coupled with a range of spectroscopic techniques in order to facilitate sub-turnover frequency studies of redox metalloenzyme mechanisms. Using this new approach we will identify and characterise short-lived catalytic intermediates and probe the fundamental coordination chemistry that equips metalloenzymes (Nature’s machines), with such remarkable efficiency.
Academic Entry Requirements
UK Bachelor Degree with at least 2:1 in a relevant subject or overseas equivalent.
Evidence of English language comparable to ILETS 6.0 if applicable.
How to Apply
Please submit your online application
https://srs.le.ac.uk/sipr/sits.urd/run/siw_ipp_lgn.login?process=siw_ipp_app&code1=RCHF00FN&code2=0093

Include with your application
• CV
• Degree Certificates and Transcripts
• Details of any study currently being undertaken
• Enter the supervisor name and project title in the Proposal Section (no proposal required)
• Enter contact details of two academic referees in the boxes provided or upload reference letters if already obtained.
• Evidence of English language.
• In the funding section include: Ref CSE-Ash

When you have submitted your application we will send you a personal statement form to complete separately.