A5029105189- Photochemistry and Electron Transfer Studies
- Spectroscopy and Quantum Chemical Studies
- Photoreceptor and optogenetics research
- Electromagnetic Fields and Biological Effects
- Electrochemical Analysis and Applications
- Electron Spin Resonance Studies
- Magnetic and Electromagnetic Effects
- Molecular Junctions and Nanostructures
- Ionic liquids properties and applications
- Biofield Effects and Biophysics
- Molecular spectroscopy and chirality
- Quantum optics and atomic interactions
- Spaceflight effects on biology
- Quantum Information and Cryptography
- Advanced NMR Techniques and Applications
- Magnetism in coordination complexes
- Atomic and Subatomic Physics Research
- Protein Structure and Dynamics
- Conducting polymers and applications
- Synthesis and Properties of Aromatic Compounds
- Lanthanide and Transition Metal Complexes
- Enzyme Structure and Function
- Photosynthetic Processes and Mechanisms
- Light effects on plants
- Porphyrin and Phthalocyanine Chemistry
University of Exeter
2017-2025
Living Systems (United States)
2023
FH Kärnten
2021
University of Oxford
2014-2019
Oxfam
2017
Science Oxford
2016
Max Planck Institute for Polymer Research
2011-2016
Graz University of Technology
2005-2013
Max Planck Society
2012-2013
University of Graz
2013
Significance Billions of birds fly thousands kilometers every year between their breeding and wintering grounds, helped by an extraordinary ability to detect the direction Earth’s magnetic field. The biophysical sensory mechanism at heart this compass is thought rely on magnetically sensitive, light-dependent chemical reactions in cryptochrome proteins eye. Thus far, no theoretical model has been able account for <5° precision with which migratory are geomagnetic field vector. Here, using...
Understanding the rules of life is one most important scientific endeavours and has revolutionised both biology biotechnology. Remarkable advances in observation techniques allow us to investigate a broad range complex dynamic biological processes which living systems could exploit quantum behaviour enhance regulate functions. Recent evidence suggests that these non-trivial mechanical effects may play crucial role maintaining non-equilibrium state biomolecular systems. Quantum study such...
Surface layers (S-layers) are resilient two-dimensional protein lattices that encapsulate many bacteria and most archaea. In archaea, S-layers usually form the only structural component of cell wall thus act as final frontier between its environment. Therefore, crucial for supporting microbial life. Notwithstanding their importance, little is known about archaeal at atomic level. Here, we combined single-particle cryo electron microscopy, tomography, Alphafold2 predictions to generate an...
There is growing evidence that the remarkable ability of animals, in particular birds, to sense direction Earth's magnetic field relies on magnetically sensitive photochemical reactions protein cryptochrome. It generally assumed acts radical pair [FAD•- TrpH•+] formed by transfer an electron from a group three tryptophan residues photo-excited flavin adenine dinucleotide cofactor within protein. Here, we examine suitability Z•] as compass magnetoreceptor, where Z• which spin has no hyperfine...
The magnetic compass sense of migratory birds is thought to rely on magnetically sensitive radical pairs formed photochemically in cryptochrome proteins the retina. Here we assess impact protein dynamics sensitivity compass.
Abstract Migratory songbirds have the remarkable ability to extract directional information from Earth’s magnetic field 1,2 . The exact mechanism of this light-dependent compass sense, however, is not fully understood. most promising hypothesis focuses on quantum spin dynamics transient radical pairs formed in cryptochrome proteins retina 3–5 Frustratingly, much supporting evidence for theory circumstantial, largely because extreme challenges posed by genetic modification wild birds....
The radical pair model of the avian magnetoreceptor relies on long-lived electron spin coherence. Dephasing, resulting from interactions spins with their fluctuating environment, is generally assumed to degrade sensitivity this compass direction Earth's magnetic field. Here we argue that certain relaxation mechanisms can enhance its performance. We focus flavin–tryptophan in cryptochrome, currently only candidate molecule. Correlation functions for fluctuations distance between two radicals...
Birds and several other species are equipped with the remarkable ability to sense geomagnetic field for purpose of navigation orientation. The primary detection mechanism this compass is uncertain but appears originate from a truly quantum process involving spin-correlated radical pairs. In order elicit sensitivity weak magnetic fields, such as Earth's field, underlying spin dynamics must be protected fast decoherence. work, we elucidate effects relaxation on recently suggested reaction...
Birds have a remarkable ability to obtain navigational information from the Earth's magnetic field. The primary detection mechanism of this compass sense is uncertain but appears involve quantum spin dynamics radical pairs formed transiently in cryptochrome proteins. We propose here new version current model which spin-selective recombination pair not essential. One two radicals imagined react with paramagnetic scavenger via electron transfer. By means simulations cryptochrome-inspired...
We realize arbitrary-wave-form-based control of spin-selective recombination reactions radical pairs in the low-magnetic-field regime. To this end, we extend gradient-ascent pulse engineering (GRAPE) paradigm to allow for optimizing reaction yields. This overcomes drawbacks previously suggested time-local optimization approaches pairs, which were limited high biasing fields. demonstrate how efficient time-global yields can be realized by gradient-based methods augmented time blocking, sparse...
A set of seven bis(triarylamine) mixed-valence radical cations with different bridging moieties were investigated by temperature-dependent electron paramagnetic resonance (EPR) spectroscopy in methylene chloride and ortho-dichlorobenzene to evaluate the thermal transfer rate constants. The bridges used comprise [2,2]paracyclophane [3,3]paracyclophane as well fully conjugated phenylene spacers. cyclophanes serve model structures for studying intermolecular solid state materials. activation...
We describe the experimental investigation of time-resolved magnetic field effects in exciplex-forming organic donor–acceptor systems. In these systems, photoexcited acceptor state is predominantly deactivated by bimolecular electron transfer reactions (yielding radical ion pairs) or direct exciplex formation. The delayed fluorescence emitted magnetosensitive if reaction pathway involves loose pair states. This effect results from coherent interconversion between electronic singlet and...
To address the question whether donor substituents can be utilized to accelerate hole transfer (HT) between redox sites attached in para- or meta-positions a central benzene bridge, we investigated three series of mixed valence compounds based on triarylamine centers that are connected bridge via alkyne spacers at and meta-positions. The electron density was tuned by with different donating accepting character. By analyzing optical spectra DFT computations show HT properties independent for...
Long-lived spin coherence and rotationally ordered radical pairs have previously been identified as key requirements for the pair mechanism of avian magnetic compass sense. Both criteria are hard to meet in a biological environment, where thermal motion radicals creates dynamic disorder drives efficient relaxation. This has long cited major stumbling block hypothesis. Here we combine Redfield relaxation theory with analytical solutions rotational diffusion equation assess impact restricted...
A visual magnetic sense in migratory birds has been hypothesized to rely on a radical pair reaction the protein cryptochrome. In this model, sensitivity originates from coherent spin dynamics, as radicals couple nuclei via hyperfine interactions. Prior studies have often neglected electron–electron dipolar (EED) coupling hypothesis. We show that EED interactions suppress anisotropic response geomagnetic field by mechanism cryptochrome and attenuation is unlikely be mitigated mutual...
A widespread hypothesis ascribes the ability of migratory birds to navigate over large distances an inclination compass realized by protein cryptochrome in birds' retinae. Cryptochromes are activated blue light, which induces a radical pair state, spin dynamics may become sensitive earth's weak magnetic fields. The information is encoded and passed on downstream processes structural rearrangements protein, details remain vague. We utilize extensive all-atom molecular simulations probe...
Abstract Quantum sensing enables the ultimate precision attainable in parameter estimation. Circumstantial evidence suggests that certain organisms, most notably migratory songbirds, also harness quantum-enhanced magnetic field via a radical-pair-based chemical compass for precise detection of weak geomagnetic field. However, what underpins acuity such operating noisy biological setting, at physiological temperatures, remains an open question. Here, we address fundamental limits inferring...
The driving-force dependence of bimolecular fluorescence quenching by electron transfer in solution, the Rehm-Weller experiment, is revisited. One three long-standing unsolved questions about features this experiment carefully analysed here, that is, there a diffusional plateau? New experimental rates are compiled for single donor, 2,5-bis(dimethylamino)-1,3-benzenedicarbonitrile, and eighteen acceptors acetonitrile. data framework differential encounter theory using an extended version...
Many birds are endowed with a visual magnetic sense that may exploit magnetosensitive radical recombination processes in the protein cryptochrome. In this widely accepted but unproven model, geomagnetic sensitivity is suggested to arise from variations rate of pair radicals, whose unpaired electron spins undergo coherent singlet-triplet interconversion field by coupling nuclear via hyperfine interactions. However, simulations conventional mechanism (RPM) predicted only tiny...
The magnetic compass of migratory birds is thought to rely on a radical pair reaction inside the blue-light photoreceptor protein cryptochrome. sensitivity such sensor weak external fields determined by variety interactions, including electron-nuclear hyperfine interactions. Here, we investigate implications thermal motion, focusing fluctuations in dihedral and librational angles flavin adenine dinucleotide (FAD) tryptophan (Trp) radicals cryptochrome 4a from European robin (Erithacus...
This report summarizes the effects of anthropogenic radiofrequency electromagnetic fields with frequencies above 100 MHz on flora and fauna presented at an international workshop held 5-7 November 2019 in Munich, Germany. Anthropogenic these are commonplace; e.g., originating from transmitters used for terrestrial radio TV broadcasting, mobile communication, wireless internet networks, radar technologies. The flora, fauna, ecosystems not well studied. For high exceeding MHz, only...
Cryptochrome is currently the major contender of a protein to underpin magnetoreception, ability sense Earth's magnetic field. Among various types cryptochromes, cryptochrome 4 has been identified as likely magnetoreceptor in migratory birds. All-atom molecular dynamics (MD) studies have offered first insights into structural but are limited short time scale due large computational demands. Here, we employ coarse-grained MD simulations investigate emergence long-lived states and...
The temperature dependence of the rotational correlation times, τ(c), nitroxide spin probes TEMPO, TEMPOL, TEMPAMINE, and Fremy's salt in ionic liquids 1-ethyl-3-methylimidazolium ethylsulfate, 1-butyl-3-methylimidazolium hexafluorophosphate, tetrafluoroborate, tetrafluoroborate is scrutinized. rotation times vary between 54 1470 ps at 300 K. Within a range 280-380 K, tumbling well described by extended Debye-Stokes-Einstein law. hydrodynamic radii are smaller than geometrical though. This...
This study addresses magnetic field effects in exciplex forming donor-acceptor systems. For moderately exergonic systems, the and locally excited fluorophore emission are found to be magneto-sensitive. A previously introduced model attributing this finding state reversibility is confirmed. Systems characterised by a free energy of charge separation up approximately -0.35 eV exhibit effect on fluorophore. simple three-state introduced, which uses reaction distance asymmetric electron transfer...