A5091898495- Photosynthetic Processes and Mechanisms
- Enzyme Structure and Function
- Photoreceptor and optogenetics research
- Spectroscopy and Quantum Chemical Studies
- Advanced X-ray Imaging Techniques
- Advanced Electron Microscopy Techniques and Applications
- Biocrusts and Microbial Ecology
- Algal biology and biofuel production
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Protein Structure and Dynamics
- ATP Synthase and ATPases Research
- Mitochondrial Function and Pathology
- Amino Acid Enzymes and Metabolism
- Biochemical and Molecular Research
- Light effects on plants
- X-ray Spectroscopy and Fluorescence Analysis
- Quinazolinone synthesis and applications
- Metal-Catalyzed Oxygenation Mechanisms
- Microbial Natural Products and Biosynthesis
- Microfluidic and Bio-sensing Technologies
- Advanced Chemical Physics Studies
- Chemical Reactions and Isotopes
- RNA and protein synthesis mechanisms
- Diatoms and Algae Research
Deutsches Elektronen-Synchrotron DESY
2017-2022
Center for Free-Electron Laser Science
2017-2022
Universität Hamburg
2017-2022
John Wiley & Sons (Germany)
2022
Foundation for Research and Technology Hellas
2015-2021
Massachusetts Institute of Technology
2016
Arizona State University
2011-2015
National Hellenic Research Foundation
2010-2015
National Centre of Scientific Research "Demokritos"
1998-2008
University of Florence
2004
Abstract The new European X-ray Free-Electron Laser is the first free-electron laser capable of delivering pulses with a megahertz inter-pulse spacing, more than four orders magnitude higher previously possible. However, to date, it has been unclear whether would indeed be possible measure high-quality diffraction data at pulse repetition rates. Here, we show that structures can obtained using currently available operating conditions XFEL. We present two complete sets, one from well-known...
A homodimeric complex for anaerobic photosynthesis In plants, algae, and cyanobacteria, large molecular complexes—photosystems I II—convert light energy into chemical energy, releasing oxygen as a by-product. This oxygenic is critical maintaining Earth's atmospheric oxygen. At their cores, photosystems II contain heterodimeric reaction center. Reaction centers evolved in an atmosphere lacking oxygen, the ancestral was likely homodimeric, encoded by single gene. Gisriel et al. describe...
Abstract To advance microfluidic integration, we present the use of two-photon additive manufacturing to fold 2D channel layouts into compact free-form 3D fluidic circuits with nanometer precision. We demonstrate this technique by tailoring nozzles and mixers for time-resolved structural biology at X-ray free-electron lasers (XFELs). achieve submicron jets speeds exceeding 160 m s −1 , which allows megahertz XFEL repetition rates. By integrating an additional orifice, implement a low...
Serial X-ray crystallography allows macromolecular structure determination at both free electron lasers (XFELs) and, more recently, synchrotron sources. The time resolution for serial experiments has been limited to millisecond timescales with monochromatic beams. polychromatic, "pink", beam provides a than two orders of magnitude increased photon flux and hence accessing much shorter in diffraction Here we report the different protein samples by merging pink-beam patterns from many...
Unravelling the interaction of biological macromolecules with ligands and substrates at high spatial temporal resolution remains a major challenge in structural biology. The development serial crystallography methods X-ray free-electron lasers subsequently synchrotron light sources allows new approaches to tackle this challenge. Here, polyimide tape drive designed for mix-and-diffuse experiments is reported. structure lysozyme bound by competitive inhibitor chitotriose was determined using...
X-ray crystallography is one of the main methods to determine atomic-resolution 3D images whole spectrum molecules ranging from small inorganic clusters large protein complexes consisting hundred-thousands atoms that constitute macromolecular machinery life. Life not static, and unravelling structure dynamics most important reactions in chemistry biology essential uncover their mechanism. Many these reactions, including photosynthesis which drives our biosphere, are light induced occur on...
With an aim toward glycogenolysis control in Type 2 diabetes, we have investigated via kinetic experiments and computation the potential of indirubin (IC₅₀ > 50 μM), indirubin-3'-oxime = 144 nM), KT5720 (K(i) 18.4 nM) staurosporine 0.37 as phosphorylase kinase (PhKγtrnc) ATP-binding site inhibitors, with latter two revealed potent inhibitors low nM range. Because lack structural information, exploited information from homologous complexes to direct silico calculations (docking, molecular...
Abstract The world’s first superconducting megahertz repetition rate hard X-ray free-electron laser (XFEL), the European XFEL, began operation in 2017, featuring a unique pulse train structure with 886 ns between pulses. With its rapid rate, XFEL may alleviate some of increasing demand for beamtime, particularly membrane protein serial femtosecond crystallography (SFX), leveraging orders-of-magnitude faster data collection. Here, we report SFX experiment, where determined 2.9 Å-resolution...
Serial crystallography at conventional synchrotron light sources (SSX) offers the possibility to routinely collect data room temperature using micrometre-sized crystals of biological macromolecules. However, SSX collection is not yet as routine and currently takes significantly longer than standard rotation series cryo-crystallography. Thus, its use for high-throughput approaches, such fragment-based drug screening, where measure physiological temperatures would be a great benefit, impaired....
In nature, protein subunits containing multiple iron–sulfur clusters often mediate the delivery of reducing equivalents from metabolic pathways to active site redox proteins. The de novo design proteins should include engineering a conduit for electrons and site, in which centers are arranged controlled manner. Here, we describe designed three-helix protein, DSD-bis[4Fe-4S], that coordinates two within its hydrophobic core. exploits pseudo two-fold symmetry scaffold, DSD, is homodimeric...
The new European X-ray Free-Electron Laser (European XFEL) is the first free-electron laser capable of delivering intense pulses with a megahertz interpulse spacing in wavelength range suitable for atomic resolution structure determination. An outstanding but crucial question whether use pulse repetition rate nearly four orders magnitude higher than previously possible results unwanted structural changes due to either radiation damage or systematic effects on data quality. Here, separate...
Abstract Introduction Mammalian glutamate dehydrogenase (hGDH1 in human cells) interconverts to α‐ketoglutarate and ammonia while reducing NAD(P) NAD(P)H. During primate evolution, humans great apes have acquired hGDH2, an isoenzyme that underwent rapid evolutionary adaptation concomitantly with brain expansion, thereby acquiring unique catalytic regulatory properties permitted its function under conditions inhibitory ancestor hGDH1. Although the 3D‐structures of GDHs, including hGDH1, been...
It was shown recently [Goussias, C., Ioannidis, N., and Petrouleas, V. (1997) Biochemistry 36, 9261−9266] that incubation of photosystem II preparations with NO at −30 °C in the dark results formation a new intermediate water-oxidizing complex. This is characterized by an EPR signal centered g = 2 prominent manganese hyperfine structure. We have examined detailed structure using difference spectroscopy. facilitated observations can be completely removed without decrease or modification...
The gene coding for the aminoglycoside adenylyltransferase (aadA6) from a clinical isolate of Pseudomonas aeruginosa was cloned and expressed in Escherichia coli strain BL21(DE3)pLysS. overexpressed enzyme (AadA6, 281 amino-acid residues) carboxy-terminal truncated variant molecule ([1-264]AadA6) were purified to near homogeneity characterized. Light scattering experiments conducted under low ionic strength supported equilibrium between monomeric homodimeric arrangements subunits. Circular...
Incubation of photosystem II preparations with NO at −30 °C results in the slow formation a unique state water-oxidizing complex (WOC), which was recently identified as Mn(II)-Mn(III) dimer [Sarrou, J., Ioannidis, N., Deligiannakis, Y., and Petrouleas, V. (1998) Biochemistry 37, 3581−3587]. Evolution EPR signal proceeds through one or more intermediates [Goussias, C., (1997) 36, 9261−9266]. In an effort to identify these intermediates, we have examined time course evolution presence absence...
Native cytochrome c6 was purified from an extract of strain BP-1 the thermophilic cyanobacterium Thermosynechococcus elongatus. The protein crystallized, and with only slight modifications buffer vapour-diffusion conditions two different space groups were observed, namely H3 C2. Both crystal structures solved; they contained three six molecules per asymmetric unit refined to 1.7 2.25 Å resolution, respectively. To date, structure native T. elongatus has been reported as a monomer using NMR...
In spinach photosystem II (PSII) membranes, the tetranuclear manganese cluster of oxygen-evolving complex (OEC) can be reduced by incubation with nitric oxide at −30 °C to a state which is characterized an Mn2(II, III) EPR multiline signal [Sarrou, J., Ioannidis, N., Deligiannakis, Y., and Petrouleas, V. (1998) Biochemistry 37, 3581−3587]. This was recently assigned S-2 OEC [Schansker, G., Goussias, C., V., Rutherford, A. W. (2002) 41, 3057−3064]. On basis spectroscopy flash-induced oxygen...