A5083511477- Enzyme Structure and Function
- Advanced Electron Microscopy Techniques and Applications
- Photoreceptor and optogenetics research
- Spectroscopy and Quantum Chemical Studies
- Magnetism in coordination complexes
- Photosynthetic Processes and Mechanisms
- Protein Structure and Dynamics
- Advanced X-ray Imaging Techniques
- Electron Spin Resonance Studies
- Radical Photochemical Reactions
- Hemoglobin structure and function
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Photochemistry and Electron Transfer Studies
- Antimicrobial agents and applications
- Organic and Molecular Conductors Research
- Antimicrobial Peptides and Activities
- Biochemical and Molecular Research
- Metal-Catalyzed Oxygenation Mechanisms
- Photochromic and Fluorescence Chemistry
- Advanced Chemical Physics Studies
- Click Chemistry and Applications
- Porphyrin and Phthalocyanine Chemistry
- Catalytic C–H Functionalization Methods
- Porphyrin Metabolism and Disorders
University of Potsdam
2018-2025
Max Planck Institute for the Structure and Dynamics of Matter
2016-2020
Diamond Light Source
2017-2020
Goethe University Frankfurt
2013-2017
Canada Research Chairs
2016-2017
University of Toronto
2014-2017
University of New Brunswick
2016-2017
SPring-8
2017
Tohoku University
2017
Japan Synchrotron Radiation Research Institute
2017
The vibrational label SCN is used to report on local structural dynamics in a protein revealing spectral diffusion picosecond scale. spectra are compared the response of methylthiocyanate solvents with different polarity and hydrogen-bonding capabilities.
Active sites that move together Enzymes often form dimers or higher-order oligomers, even when each active site is isolated and the reactions are simple. But effect of a neighbor can be profound. Mehrabi et al. used photolabile compound to initiate reaction in enzyme fluoroacetate dehalogenase, which they could follow by time-resolved serial synchrotron crystallography. Snapshots revealed coupled allosteric motions between two dimeric enzyme. Each traded ability bind substrate catalyze...
The development of serial crystallography has been driven by the sample requirements imposed X-ray free-electron lasers. Serial techniques are now being exploited at synchrotrons. Using a fixed-target approach to high-throughput sampling, it is demonstrated that high-quality data can be collected from myoglobin crystals, allowing room-temperature, low-dose structure determination. combination arrays and fast, accurate translation system allows collection high hit rates with low consumption.
We demonstrate that several visible-light-mediated carbon-heteroatom cross-coupling reactions can be carried out using a photoactive NiII precatalyst forms in situ from nickel salt and bipyridine ligand decorated with two carbazole groups (Ni(Czbpy)Cl2 ). The activation of this towards follows hitherto undisclosed mechanism is different previously reported light-responsive complexes undergo metal-to-ligand charge transfer. Theoretical spectroscopic investigations revealed irradiation...
Abstract A comprehensive insight into ultrafast dynamics of photo-switchable materials is desired for efficient control material properties through light excitation. Here, we study a polycrystalline spin crossover thin film as prototypical example and reveal the sequential photo-switching dynamics, from local molecular rearrangement to global lattice deformation. On earliest femtosecond timescale, structural occurs within constant unit-cell volume two-step process, involving initial...
The advent of ultrafast highly brilliant coherent X-ray free-electron laser sources has driven the development novel structure-determination approaches for proteins, and promises visualization protein dynamics on sub-picosecond timescales with full atomic resolution. Significant efforts are being applied to sample-delivery systems that allow these unique be most efficiently exploited high-throughput serial femtosecond crystallography. Here, next iteration a fixed-target crystallography chip...
Serial synchrotron crystallography (SSX) is an emerging technique for static and time-resolved protein structure determination. Using specifically patterned silicon chips sample delivery, the `hit-and-return' (HARE) protocol allows efficient data collection. The specific pattern of crystal wells in HARE chip provides direct access to many discrete time points. allow optical excitation as well on-chip mixing reaction initiation, making a large number systems amenable studies. Loading...
Vibrational energy transfer (VET) is believed to play an important role in protein function. Theoretical studies predict highly directional, anisotropic VET proteins. Distinct pathways which connect distant functional sites proteins have been proposed by simulations, indicating a function allosteric communication. Experimental evidence for such pathways, however, lacking. In small molecules, ultrafast vibrational pump–probe spectroscopy has used investigate between different parts of...
Abstract Photoexcitation of spin crossover (SCO) complexes can trigger extensive electronic transitions and transformation molecular structure. However, the precise nature associated ultrafast structural dynamics remains elusive, especially in solid state. Here, we studied a single‐crystal SCO material with femtosecond electron diffraction (FED). The unique capability FED allows us to directly probe atomic motions track changes within crystal lattice. By monitoring time‐dependent Bragg...
For the two proteins myoglobin and fluoroacetate dehalogenase, we present a systematic comparison of crystallographic diffraction data collected by serial femtosecond (SFX) synchrotron crystallography (SSX). To maximize comparability, used same batch micron-sized crystals, sample delivery device, analysis software. Overall figures merit indicate that both radiation sources are equivalent quality. proteins, reasonable statistics can be obtained with approximately 5000 room-temperature images...
Distance matters: Interpretation of infrared spectra regularly involves the assignment absorption bands to certain functional groups molecule. Distance-dependent vibrational energy transfer can be used for exact band in molecules which is difficult and quantum chemical computations are contradictory. As a service our authors readers, this journal provides supporting information supplied by authors. Such materials peer reviewed may re-organized online delivery, but not copy-edited or typeset....
The indexing methods currently used for serial femtosecond crystallography were originally developed experiments in which crystals are rotated the X-ray beam, providing significant three-dimensional information. On other hand, shots from both free-electron lasers and synchrotron still images, few data available arise only curvature of Ewald sphere. Traditional thus less well suited to image processing. Here, a new method is presented with aim maximizing information use given known unit-cell...
Hexokinase catalyzes the first step of glycolysis, transferring a phosphate group from adenosine triphosphate (ATP) to glucose (Glc) produce glucose-6-phosphate (Glc-6P) and diphosphate (ADP). This enzymatic reaction is crucial in biochemistry medical diagnostics, such as Glc level assessments using hexokinase/glucose-6-phosphate dehydrogenase method. In this study, we employ two-dimensional infrared (2DIR) spectroscopy monitor hexokinase activity real time by observing asymmetric stretching...
Abstract One of the most basic molecular photophysical processes is that spin transitions and intersystem crossing between excited states surfaces. The change in affects spatial distribution electron density through orbit coupling interaction. subsequent nuclear reorganization reports on full extent induced distribution, which can be treated similarly to intramolecular charge transfer with effective reaction coordinates depicting transition. Here, single-crystal [Fe II (bpy) 3 ](PF 6 ) 2 , a...
Antimicrobial resistance (AMR) is a severe threat to modern health care and must be addressed prevent millions of deaths in the coming decades. polymers (APs) do not provoke resistances are promising alternatives conventional antibiotics. Classic APs possess an amphiphilic structure (cationic hydrophobic). Herein we question necessity amphiphilicity find that hydrophobicity essential quality these polymers. Combining cationic monomers with hydrophilic subunits containing hydrogen bond donors...
Photolabile protection groups (PPGs) pertain broad application potential as they allow spatially and temporal controlled release of the protected group. While photochemistry many PPGs has been studied in detail, data aequous conditions or depending on pH are extremely rare. However for applications under biological water knowledge about these is critical. Here we pH-dependent reaction dynamics para-hydroxy-phenacyl (pHP), one prominent example PPGs, by ultrafast transient absorption...
Polymeric antimicrobial peptide mimics are a promising alternative for the future management of daunting problems associated with resistance. However, development successful polymers (APs) requires careful control factors such as amphiphilic balance, molecular weight, dispersity, sequence, and architecture. While most earlier developed APs focus on random linear copolymers, advanced architectures proves to be more potent. It is recently multivalent bottlebrush improved antibacterial...
Carbohydrates constitute one of the four key classes biomacromolecules but have not been studied by 2D-IR spectroscopy so far. Similarly as for proteins, a lack native vibrational reporter groups, combined with their huge structural diversity, leads to spectrally congested infrared spectra already single carbohydrates. Biophysical studies are further impeded strong overlap between water modes and carbohydrate modes. Here, we demonstrate application known group thiocyanate (SCN) label in...
Abstract Antimicrobial polymers are a promising alternative to conventional antibiotics in the fight against antimicrobial resistance. Cationic bottle brush copolymers have shown be superior linear topologies previous studies. Herein, aspect ratio of such is varied creating differently shaped confined unimolecular structures with varying degrees side chain mobility. Using reversible addition‐fragmentation chain‐transfer (RAFT) polymerization, brushes produced one‐pot procedure. The...
The impact of the incorporation a non-natural amino acid (NNAA) on protein structure, dynamics, and ligand binding has not been studied rigorously so far. NNAAs are regularly used to modify proteins post-translationally in vivo vitro through click chemistry. Herein, structural characterisation azidohomoalanine (AZH) into model domain PDZ3 is examined by means NMR spectroscopy X-ray crystallography. structure dynamics apo state AZH-modified remain mostly unperturbed. Furthermore, two peptides...
A common challenge for pump-probe studies of structural dynamics at X-ray free-electron lasers (XFELs) is the determination time zero (T0)-the an optical pulse (e.g., laser) arrives coincidently with probe a XFEL pulse) sample position. In some cases, T0 might be extracted from sample's observed response itself, but generally, independent robust method required or would superior to inferred T0. this paper, we present how in ultrafast melting bismuth can exploited quickly performed, reliable...