A5083879334- Photoreceptor and optogenetics research
- Light effects on plants
- Photosynthetic Processes and Mechanisms
- Spectroscopy and Quantum Chemical Studies
- Photochemistry and Electron Transfer Studies
- Protein Structure and Dynamics
- Photochromic and Fluorescence Chemistry
- DNA and Nucleic Acid Chemistry
- Circadian rhythm and melatonin
- Mass Spectrometry Techniques and Applications
- Advanced Chemical Physics Studies
- Hemoglobin structure and function
- bioluminescence and chemiluminescence research
- Protein Interaction Studies and Fluorescence Analysis
- Neurobiology and Insect Physiology Research
- Advanced Fluorescence Microscopy Techniques
- Laser-Matter Interactions and Applications
- Lipid Membrane Structure and Behavior
- Microfluidic and Capillary Electrophoresis Applications
- Advanced biosensing and bioanalysis techniques
- Enzyme Structure and Function
- CO2 Reduction Techniques and Catalysts
- Advanced Electron Microscopy Techniques and Applications
- Molecular Junctions and Nanostructures
- Bacteriophages and microbial interactions
The Ohio State University
2016-2025
Institute for Advanced Study
2025
Shanghai Jiao Tong University
2018-2025
South China Normal University
2024
Peking University
2015
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics
2015
NOAA Chemical Sciences Laboratory
2013-2015
Koç University
2008
University of North Carolina at Chapel Hill
2004-2006
University of Limerick
2006
Protein surface hydration is fundamental to its structure and activity. We report here the direct mapping of global dynamics around a protein in native molten globular states, using tryptophan scan by site-specific mutations. With 16 mutants 29 different positions we observed two robust, distinct water layer on few ( approximately 1-8 ps) tens hundreds picoseconds 20-200 ps), representing initial local relaxation subsequent collective network restructuring, respectively. Both time scales are...
Photolyases, a ubiquitous class of flavoproteins, use blue light to repair DNA photolesions. In this work, we determined the structural mechanism photolyase-catalyzed cyclobutane pyrimidine dimer (CPD) lesion using time-resolved serial femtosecond crystallography (TR-SFX). We obtained 18 snapshots that show time-dependent changes in four reaction loci. used these results create movie depicts CPD lesions picosecond-to-nanosecond range, followed by recovery enzymatic moieties involved...
Photolyase uses light energy to split UV-induced cyclobutane dimers in damaged DNA, but its molecular mechanism has never been directly revealed. Here, we report the direct mapping of catalytic processes through femtosecond synchronization enzymatic dynamics with repair function. We observed electron transfer from excited flavin cofactor dimer 170 ps and back repaired thymines 560 ps. Both reactions are strongly modulated by active-site solvation achieve maximum efficiency. These results...
We report experimental and theoretical studies on water protein dynamics following photoexcitation of apomyoglobin. Using site-directed mutation with femtosecond resolution, we experimentally observed relaxation a biphasic distribution time scales, 5 87 ps, around the site Trp7. Theoretical using both linear response direct nonequilibrium molecular (MD) calculations reproduced behavior. Further constrained MD simulations either frozen or revealed mechanism slow hydration processes elucidated...
Flavoproteins can function as hydrophobic sites for vitamin B(2) (riboflavin) or, in other structures, with cofactors catalytic reactions such glucose oxidation. In this contribution, we report direct observation of charge separation and recombination two flavoproteins: riboflavin-binding protein oxidase. With femtosecond resolution, observed the ultrafast electron transfer from tryptophan(s) to riboflavin protein, reaction times: approximately 100 fs (86% component) 700 (14%). The was take...
We report here our systematic studies of excited-state dynamics two common flavin molecules, FMN and FAD, in five redox states—oxidized form, neutral anionic semiquinones, fully reduced hydroquinones—in solution inert protein environments with femtosecond resolution. Using environments, we were able to stabilize semiquinone radicals thus observed their weak emission spectra. Significantly, a strong correlation between the planarity isoalloxazine ring. For bent ring structure, ultrafast from...
Protein surface hydration is fundamental to its structural stability and flexibility, water−protein fluctuations are essential biological function. Here, we report a systematic global mapping of water motions in the layer around model protein apomyoglobin both native molten globule states. With site-directed mutagenesis, use intrinsic tryptophan as local optical probe scan one at time with single-site specificity. femtosecond resolution, examined 16 mutants two states observed types...
Photolyase uses blue light to restore the major ultraviolet (UV)-induced DNA damage, cyclobutane pyrimidine dimer (CPD), two normal bases by splitting ring. Our earlier studies showed that overall repair is completed in 700 ps through a cyclic electron-transfer radical mechanism. However, fundamental processes, electron-tunneling pathways and ring splitting, were not resolved. Here, we use ultrafast UV absorption spectroscopy show CPD splits sequential steps within 90 electron tunnels...
We report here our systematic studies of the dynamics four redox states flavin cofactor in both photolyases and insect type 1 cryptochromes. With femtosecond resolution, we observed ultrafast photoreduction oxidized state adenine dinucleotide (FAD) subpicosecond neutral radical semiquinone (FADH•) tens picoseconds through intraprotein electron transfer mainly with a neighboring conserved tryptophan triad. Such make these forms unlikely to be functional photolyase/cryptochrome family. In...
Significance Hydration water around a protein is fundamental to protein’s property and function. How hydration interacts with at their interface has not been fully understood. A universal slaving model that drives fluctuations proposed, but direct experimental observation difficult challenging. Here, we directly measured dynamics side-chain relaxations temperature dependence. With extensive data, conclude the surface hydration-shell drive motions on picosecond time scales thus play critical...
Cryptochrome (CRY) is a blue-light sensitive flavoprotein that functions as the primary circadian photoreceptor in Drosophila melanogaster . The mechanism by which it transmits light signal to core clock circuitry not known. We conducted vitro studies on light-induced conformational change CRY and its effect protein–protein interaction performed vivo analysis of lifetime signaling state protein gain some insight into phototransduction. find exposure blue induces conformation similar...
In this contribution, we report studies of the nature dynamics and hydrophobic binding in protein–ligand complexes human serum albumin with 2-(2′-hydroxyphenyl)-4-methyloxazole. With femtosecond time resolution, examined orientational motion ligand, its intrinsic nuclear motions, lifetime changes phase. For comparisons, similar but chemical nanocavities, also studied same ligand micelles cyclodextrins. The interactions crevice are much stronger than those observed cyclodextrins micelles....
Human serum albumin, the most abundant protein found in blood plasma, transports a great variety of ligands circulatory system and undergoes reversible conformational transitions over wide range pH values. We report here our systematic studies solvation dynamics local rigidity these conformations using single intrinsic tryptophan (W214) residue as molecular probe. With femtosecond resolution, we observed robust bimodal distribution time scales for all isomers. The initial occurs several...
Water motion at protein surfaces is fundamental to structure, stability, dynamics, and function. By using intrinsic tryptophans as local optical probes, with femtosecond resolution, it possible probe surface-water motions in the hydration layer. Here, we report our studies of dynamics surface enzyme Staphylococcus nuclease site-specific mutations. From these WT four related mutants, which change charge distribution are able ascertain contribution solvation by side chains relatively...
In this contribution, we give a full account of the approach femtosecond, time-resolved mass spectrometry in molecular beams for studies elementary steps complex reactions and application to different systems. The level complexity varies from diatomics polyatomics, direct-mode complex-mode, one-center, two-center, four-center, uni- bimolecular reactions. systems studied are iodine, cyanogen iodide, methyl iodobenzene, 1,2-diiodotetrafluoroethane, mercury benzene· iodine complexes, iodide...
Cryptochromes are blue-light receptors mediating various light responses in plants and animals. The photochemical mechanism of cryptochromes is not well understood. It has been proposed that photoactivation involves the blue-light–dependent photoreduction flavin adenine dinucleotide via electron transport chain composed three evolutionarily conserved tryptophan residues known as “trp triad.” We investigated this hypothesis by analyzing physiological activities Arabidopsis cryptochrome 2...
The flavin cofactor in photoenzyme photolyase and photoreceptor cryptochrome may exist an oxidized state should be converted into reduced state(s) for biological functions. Such redox changes can efficiently achieved by photoinduced electron transfer (ET) through a series of aromatic residues the enzyme. Here, we report our complete characterization photoreduction dynamics with femtosecond resolution. With various site-directed mutations, identified all possible donors enzyme determined...