Increasing the brightness of near Infrared bioluminescence
Lead Research Organisation:
University College London
Department Name: Chemistry
Abstract
The most direct measurement of electronic structure is the determination of electron binding energies using photoelectron spectroscopy and as a result of recent advances in liquid microjet photoelectron spectroscopy, it is now possible to measure the photoelectron spectra of molecules in solution. The overall aim of the project is to use the new liquid-jet photoelectron spectrometer developed by HF to record photoelectron spectra and time-resolved photoelectron spectra of synthetic luciferin/luciferase complexes. This will allow us to gain new molecular-level insight into the role of the protein environment in controlling the electronic structure and the excited state dynamics following bioluminescence. Quantum chemistry calculations will be performed to unravel the effect of the protein environment on the synthetic luciferin chromophore. We will use this data, of significance in its own right, to inform the rational design of further synthetic luciferins that display a higher quantum yield.
This research will characterise new near infrared luciferins to give biological and medical researchers access to an expanded set of bioluminescent tools. This would be the first ever investigation of the electronic structure of the luciferin/luciferase species responsible for bioluminescence. It is the highest quantum yielding photochemical reaction known. A fundamental understanding of its electronic spectra will aid the rational design of synthetic analogues for other applications. The development of deep tissue imaging would greatly enhance the use of this cheap and effective imaging tool to investigate disease in whole animals.
This research will characterise new near infrared luciferins to give biological and medical researchers access to an expanded set of bioluminescent tools. This would be the first ever investigation of the electronic structure of the luciferin/luciferase species responsible for bioluminescence. It is the highest quantum yielding photochemical reaction known. A fundamental understanding of its electronic spectra will aid the rational design of synthetic analogues for other applications. The development of deep tissue imaging would greatly enhance the use of this cheap and effective imaging tool to investigate disease in whole animals.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N509577/1 | 01/10/2016 | 24/03/2022 | |||
| 1786809 | Studentship | EP/N509577/1 | 01/10/2016 | 30/09/2019 | Anand Patel |
| Description | Publications: J. Phys. Chem. A 2018, 122, 41, 8222-8228 Phys. Chem. Chem. Phys., 2017,19, 31572-31580 Phys. Chem. Chem. Phys., 2020,22, 19022-19032 Prizes: Best oral presentation at the 2019 RSC UK-Italy joint conference of photochemistry and photophysics in Lipari 2018 UCL best poster prize in Physical Chemistry Preliminary project (not included in the thesis): Synthesized novel molecular analogues of the photo-active yellow protein chromophore which has improved our understanding on how the chromophore works in its native environment (J. Phys. Chem. A 2018, 122, 41, 8222-8228, Phys. Chem. Chem. Phys., 2017,19, 31572-31580) Main project (thesis): Firefly bioluminescence occurs by the enzyme catalysed oxidation of D-luciferin to oxyluciferin in its electronically excited by a luciferase in the presence of ATP, Mg2+ and O2 co-factors. Relaxation to its ground state results in the emission of a photon of light. The wavelength of light emission can be altered by mutating the luciferase and/or synthesising analogues of luciferin. In the Anderson group, a synthetic p-extended analogue of luciferin, infraluciferin, was synthesised and exhibited a significant red shifted emission, but was ~ 100 times dimmer than D-luciferin. An understanding of the excited state dynamics of the light emitter oxyluciferin in vacuo may help to design better bioluminescent systems for analytical applications. Part one describes the results of anion photoelectron spectroscopy measurements employed to determine the electronic structure of oxyluciferin in vacuo. These were interpreted with the aid of quantum chemistry calculations performed by another PhD student. Oxyluciferin can exist in three anionic resonance forms (keto, enol and enolate). To track the dynamics of these different species, the known protected derivatives, which trap the resonance forms, were synthesised from the literature and their photoelectron measurements were recorded between wavelengths 359 - 294 nm. The excited state dynamics of the analogues were unravelled by linking spectral features with the calculated excited state energies; the work has been published (Phys. Chem. Chem. Phys., 2020,22, 19022-19032). Part two describes the synthesis of three protected p-extended resonance forms of oxyinfraluciferin and preliminary photoelectron measurements of the keto and enolate derivatives recorded at 346 nm. The synthesis features two unique cyclisation strategies to form the keto and acetyl-protected enolate derivatives. The acetyl-protected enolate derivative was successfully deacetylated in situ before running photoelectron measurements. Preliminary analysis of the 346 nm photoelectron spectra of keto and enolate derivatives provides a good starting point for future detailed spectroscopic investigations on understanding how increasing the conjugations affects the electronic structure and dynamics relative to their oxyluciferyl derivatives. |
| Exploitation Route | The excited state dynamics of oxyluciferin and its derivatives were unravelled. This has provided the foundations for understanding how increasing the conjugation affects the electronic structure and dynamics relative to their oxyluciferyl derivatives. More complex studies are being carried out by students in the Fielding group. The synthesis of the infra-oxyluciferin novel analogues may have potential applications in fluorescence imaging. The synthetic routes are novel which means that an array of novel derivatives can be synthesized and screened. Other students in the Anderson group are continuing with the development of these synthetic routes. |
| Sectors | Chemicals,Electronics,Healthcare,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology |