Mechanistic Insights into Haem Sensing by the Circadian Clock

About the Project

Haem is a small organo-transition-metal compound that plays a crucial role in various aspects of cellular biology. Traditionally, its function was thought to be limited to haemoproteins, where it serves as a tightly bound prosthetic group. However, emerging evidence has significantly expanded this perspective. Recent studies highlight a broader and more complex range of biological processes in which haem is used transiently to modulate the activity or behaviour of other proteins.

Our research focuses on PERIOD, a protein that is essential for maintaining the 24-hour rhythm of the biological clock. PERIOD can bind haem at both its Nterminal and C-terminal domains, but the functional significance of this interaction in circadian regulation remains unclear. We hypothesise that haem binding induces a substantial conformational change in PERIOD, which in turn affects its ability to interact with other core clock proteins.

The primary objectives of this research are to characterise the interaction between haem and the PERIOD protein, and to determine the resulting conformational changes in PERIOD's structure. Since PERIOD’s activity depends on its ability to form a heterodimer with the protein CRYPTOCHROME, we will also investigate how haem influences this critical protein-protein interaction.

The experimental approach will involve biophysical analyses of haem binding to PERIOD using isothermal titration calorimetry and spectroscopic techniques. In addition, we will characterise the structure and conformational dynamics of PERIOD through nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), optical plasmonic nanotweezers, and small-angle X-ray scattering (SAXS).

By elucidating how haem modulates the function of a core circadian protein, this research aims to reveal a broader regulatory role for haem—extending beyond circadian timekeeping to processes such as immune function, neurodegeneration, aging, gas sensing, and ion-channel gating.

Techniques that will be undertaken during the project

• Nuclear magnetic resonance spectroscopy,
• Electron paramagnetic resonance spectroscopy,
• Circular dichroism spectroscopy,
• UV-visible absorption spectroscopy,
• Fluorescence spectroscopy,
• Optical plasmonic nanotweezing,
• Small-angle X-Ray scattering,
• Protein expression and purification.

Funding Notes

This project is only available on a self funded basis or if you have your own sponsorship.