A5079315906- Photosynthetic Processes and Mechanisms
- Spectroscopy and Quantum Chemical Studies
- Photoreceptor and optogenetics research
- Light effects on plants
- Advanced Chemical Physics Studies
- Photochemistry and Electron Transfer Studies
- Molecular spectroscopy and chirality
- Plant and animal studies
- Mass Spectrometry Techniques and Applications
- Energy Harvesting in Wireless Networks
- Atmospheric Ozone and Climate
- Metal-Catalyzed Oxygenation Mechanisms
- NMR spectroscopy and applications
- Algal biology and biofuel production
- Laser-Matter Interactions and Applications
- Porphyrin and Phthalocyanine Chemistry
- Radio Frequency Integrated Circuit Design
- Electrochemical Analysis and Applications
- Porphyrin Metabolism and Disorders
- Antioxidant Activity and Oxidative Stress
- Redox biology and oxidative stress
- Antenna Design and Analysis
Kansas State University
2017-2024
Arizona State University
2024
Russian Academy of Sciences
2008-2013
Institute of Basic Biological Problems
2011
Abstract Photosystem I coordinates more than 90 chlorophylls in its core antenna while achieving near perfect quantum efficiency. Low energy (also known as red chlorophylls) residing the are important for transfer dynamics and yield, however, their precise location remained elusive. Here, we construct a chimeric complex Synechocystis PCC 6803 that shows enhanced absorption spectral region. We combine Cryo-EM spectroscopy to determine structure − function relationship this red-shifted...
To identify the molecular composition of low-energy states in cyanobacterial Photosystem I (PSI) Synechocystis PCC6803, we focus on high-resolution (low-temperature) absorption, emission, resonant, and nonresonant hole-burned spectra obtained for wild-type (WT) PSI three mutants. In Red_a mutant, B33 chlorophyll (Chl) is added to B31-B32 dimer; Red_b, histidine 95 (His95) PsaB (which coordinates Mg B7 Chl within His95-B7-A31-A32-cluster) replaced with glutamine (Gln), while Red_ab both...
We provide an analysis of the pigment composition reconstituted wild type CP29 complexes. The obtained stoichiometry 9 ± 0.6 Chls a and 3 b per complex, with some possible heterogeneity in carotenoid binding, is agreement 3.5 revealed by modeling low-temperature optical spectra. find that ∼50% Chl b614 lost during reconstitution/purification procedure, whereas are almost fully retained. excitonic structure nature low-energy (low-E) state(s) addressed via simulations (using Redfield theory) 5...
We report high-resolution (low-temperature) absorption, emission, and nonresonant/resonant hole-burned (HB) spectra results of excitonic calculations using a non-Markovian reduced density matrix theory (with an improved algorithm for parameter optimization in heterogeneous samples) obtained the Y16F mutant Fenna–Matthews–Olson (FMO) trimer from green sulfur bacterium Chlorobium tepidum. show that is mixture FMO complexes with three independent low-energy traps (located near 817, 821, 826...
Hole burning (HB) spectroscopy and modeling studies reveal significant changes in the excitonic structure dynamics several mutants of FMO trimer from Chlorobaculum tepidum. The excited-state decay times (T1) high-energy excitons are significantly modified when mutation occurs near bacteriochlorophyll (BChl) 1 (V152N mutant) or BChl 6 (W184F). Longer (averaged) T1 highest-energy V152N W184F suggest that site energies BChls 6, believed to play an important role receiving excitation baseplate...
Bioinspired benzimidazole-phenol constructs with an intramolecular hydrogen bond connecting the phenol and benzimidazole have been synthesized to study both proton-coupled electron transfer (PCET) excited-state proton (ESIPT) processes. Strategic incorporation of a methyl group disrupts coplanarity between aromatic units, causing pronounced twist, weakening bond, decreasing redox potential, reducing chemical reversibility, quenching fluorescence emission. Infrared spectroelectrochemistry...
Excitonic interactions between two closely separated bacteriochlorophyll a molecules (BChls) in the special pair of reaction center (RC) purple bacteria determine positions and relative oscillator strengths its excitonic components. While absorption lower band is well-defined, position intensity upper (PY+) are still under debate. Recent 77 K two-dimensional electronic spectroscopy data on Rba. capsulatus suggested that PY+ component absorbs at ∼840 nm, i.e., significantly energy than...
Significant protein rearrangement upon excitation and energy transfer in Fenna–Matthews–Olson of Prosthecochloris aestuarii results a modified landscape, which induces more changes pigment site energies than predicted by the "standard" hole-burning theory. The are elucidated simulations while investigating effects site-dependent disorder, both static (site-energy distribution widths) dynamic (spectral density shapes). resulting optimized their fluctuations consistent with relative...
The Fenna–Matthews–Olson (FMO) light-harvesting antenna protein of green sulfur bacteria is a long-studied pigment–protein complex which funnels energy from the chlorosome to reaction centre where photochemistry takes place. structure FMO Chlorobaculum tepidum known as homotrimeric containing eight bacteriochlorophyll per monomer. Owing this has strong intra-monomer and weak inter-monomer electronic coupling constants. While long-lived (sub-picosecond) coherences within monomer have been...
The PSI3–IsiA18 supercomplex is one of the largest and most complicated assemblies in photosynthesis. IsiA ring, composed 18 monomers (IsiA18) surrounding PSI trimer (PSI3), forms under iron-deficient conditions cyanobacteria acts as a peripheral antenna. Based on structure recently determined via cryo-EM imaging, we model various optical spectra IsiA18 ring. Comparison absorption emission isolated full ring reveals that about 2.7 chlorophylls (Chls) are lost monomers. best fits for obtained...
The LH2 antenna complex of the purple bacterium Allochromatium vinosum has a distinct double peak structure 800 nm band (B800). Several hypotheses were proposed to explain its origin. Recent 77 K two-dimensional electronic spectroscopy data suggested that excitonic coupling dimerized bacteriochlorophylls (BChls) within B800 ring is largely responsible for split [M. Schröter et al., J. Phys. Chem. Lett. 2018, 9, 1340]. Here we argue interactions between BChls in ring, though present, are weak...
We present a time-resolved measurement of the photodissociation and photoisomerization dynamics bromoform (CHBr3) in mono- di-cationic states produced by near-infrared (NIR) strong-field ionization. The dissociation process is probed NIR-induced Coulomb explosion imaging. find that for channels involving production HBr Br2 fragments, which require formation new bonds, appears to be delayed with respect primary C–Br bond channel. Ab initio molecular simulations support observed delay....
The FennaMatthewsOlson (FMO) antenna complex from the green sulfur bacterium Chlorobaculum (C.) tepidum is an important model protein to study exciton dynamics and excitation energy transfer in photosynthetic complexes.Single point mutations provide excellent opportunity for of structure interexciton level relaxation.In this bacterium, harvested by chlorosomes funnelled via baseplate pigments FMO trimers reaction center (RC), where photochemistry takes place.The C. was solved revealed a...
Low-temperature persistent and transient hole-burning (HB) spectra are presented for the triple hydrogen-bonded L131LH + M160LH M197FH mutant of Rhodobacter sphaeroides. These expose heterogeneous nature P-, B-, H-bands, consistent with a distribution electron transfer (ET) times excitation energy (EET) rates. Transient P+QA– holes observed fast (tens picoseconds or faster) ET reveal strong coupling to phonons marker mode(s), while bleached in fraction reaction centers long-lived excited...