Neutrons techniques such as Neutron Small Angle Scattering (SANS), Neutron Macro-molecular Crystallography (NMX), Neutron Reflection (NR) are the popular non invasive probes in life sciences and health. All these neutronic instrumentation have been employed in studying the morphology of large molecules and macro-molecular complexes , the drug molecules and their interactions with the...
Dancing water molecules on the surface of soluble proteins provide the essential lubricant for macromolecular function. Surprisingly, polymers attached to protein surfaces have been reported to replace hydration water and bring inactive dry proteins back to life (Perriman et al. (2010) Nat Chem 2, 622; Gallat et al. (2012) JACS 134, 13168). The mechanism behind polymer-assisted protein motions...
Amyloid fibrils are self-assembled protein filaments, the deposition of which in tissues causes amyloidosis. Recently, much attention has been paid to polymorphism, where proteins form various amyloid fibrils that differ in structure and show different levels of cytotoxicity depending on fibrillation conditions. Since intramolecular motions in the fibrils are considered to play a crucial role...
Protein dynamics is pivotal to fulfill protein function. Apolipoprotein B-100 is a giant monomeric protein with a fascinating dynamical history: it mediates the conversion from very low density lipoprotein (VLDL, ~50 nm) to low density lipoprotein (LDL, 22 nm). As a key-player in the cholesterol transport system, the protein is intimately linked to the development of atherosclerosis and...
Intrinsically disordered proteins (IDPs) adopt a wide variety of conformations in solution, without a distinct equilibrium structure. Here, we investigate the dynamics of IDPs, using the antimicrobial saliva protein Histatin 5 as model. A suitable technique for this purpose is quasi- elastic neutron scattering (QENS), which through the incoherent scattering probes the self- diffusion of...
Hydrated proteins undergo a dynamical transition (DT) at $T_d$ ≈ 180-230 K. The transition is associated with the activation of protein dynamics on the ps-ns time scale, suitably detected by Elastic Incoherent Neutron Scattering (EINS). The DT has been also observed in other biomolecules and is deemed necessary for biological functionality. Surprisingly, a DT has been recently found in a...
Cancer is one of the major threats to our health on a global scale. In order to battle these diseases while maintaining the quality of life for patients it is important to find anticancer drugs with a high selectivity for the target cancer cell. Melittin, a peptide found in Honey bee venom has long been known for its antimicrobial effects. Later studies have also shown Melittin to be effective...
The neutron backscattering spectrometer SPHERES (SPectrometer for High Energy RESolution) at MLZ is a third generation backscattering spectrometer with focusing optics and phase-space transform (PST) chopper. It covers a dynamic range of ± 31μeV with a high resolution of about 0.66μeV and a good signal-to-noise ratio. The instrument performance has been improved over the recent years by...
Following molecular dynamics during the temporary evolution of kinetically changing samples is a major challenge. With recent developments of analysis frameworks, accessing the short-time self-diffusive properties of protein solutions by measuring specific energy transfers via neutron backscattering, kinetically changing samples can be investigated. The immobile fraction, determined by...
Neutron spin echo (NSE) spectroscopy provides the ultimate energy resolution in quasi-elastic thermal and cold neutron scattering spectroscopy. In terms of Fourier-time (τ) – or equivalently in terms of the accessible energy (E) – high resolution means the extension of τ (respectively E) into to the regime of μs (neV). The recently upgraded Jülich neutron spin echo spectrometer J-NSE “PHOENIX”...
Casein kinase II (CK2), is a serine / threonine kinase ubiquitously distributed among eukaryotic cells, is known to be involved in the cell cycle and cell survival and proliferation. CK2 is one of the drug target proteins, because the relationship between CK2 over-expression and carcinogenesis and cancer metastasis has been pointed out. We aimed to elucidate the hydrogen bonding network...
Biological samples often show a sufficiently broad spectral range where light absorption does not play a dominant role. This enables in situ sample control using dynamic and static light scattering techniques. Many biological samples undergo a slow aggregation process during the comparatively long neutron data collection times. If the aggregates are staying few in number and/or if their form...
Understanding the structure and dynamics of phospholipid membranes is of paramount importance for biophysics, biology and medical sciences. Virtually every living organisms is comprised of several of those membranes that provide a variety of functions, ranging from the separation of volumes to more complex functions like nutrient or information transport across the membrane.
All those...
KWS-2 represents a classical pinhole SANS diffractometer where, combining the conventional mode using different neutron wavelengths and detection distances with the focusing mode using MgF2 lenses, a wide Q-range between 1 x 10-4 and 1 Å-1 can be explored. The high neutron flux, comparable with that of the world leading SANS instruments, which is supplied by the neutron delivery system (cold...
Candida glabrata has been known as a non-pathogenic yeast found in healthy humans, but the number of infections caused by it has increased, making understanding its virulence an urgent task. In our multidisciplinary effort, we combine methods to produce C. glabrata strains with well-defined genetic modifications of virulence/resistance factors(1) with characterization of their membrane...
Proteins are of enormous importance to life on earth. They have a multitude of different functions in all organisms and can work as enzymes, gene regulators, structural components, transporters, and receptors. Most drugs act on proteins. The structures and mechanisms of proteins are therefore prominent topics in life science research.
Access to both state-of-the-art X-ray (MAX IV) and...
Neutron single crystal diffraction provides an experimental method for the direct location of hydrogen and deuterium atoms in biological macromolecules, thus providing important complementary information to that gained by X-ray crystallography. At the FRM II neutron source in Garching near Munich the neutron single crystal diffractometer BIODIFF, a joint project of the Forschungszentrum Jülich...
Proteins are an important component in many medical and food products, and the long-time properties of these products are directly dependent on the stability of their proteins. To enhance this stability it has become common to add disaccharides in general, and trehalose in particular. However, the mechanisms by which disaccharides stabilize proteins and other biological materials are still not...
Many low molecular weight compounds and peptides are capable of forming supramolecular complexes. In the form of such complexes, the molecules are capable of multicenter cooperative binding to target proteins. It is advisable to study these complexes using small-angle scattering methods in combination with molecular dynamics modeling in the free diffusion approach.
When studying the mechanism...
Proteome adaptation to high pressure in Archaea is still an open debate. Whole genome comparative studies could not identify a clear adaptation pattern, and HP adaptation is often considered as concomitant to another adaptation, for instance to high or low temperature.
Studies on whole cells of the near isogenic HP-adapted T. barophilus (T=85°C, p=400bars, piezophilic) and HP-sensitive *T....
Proteins are essential macronutrients in the human diet, being fundamental in body structure and functions. The protein digestibility depends not only on their composition but also on food structure, which in turn can be influenced by different types of processing.
We monitored degradation kinetics of the structure during simulated gastric and intestinal digestion, and analyzed its impact on...
Mucus is a highly viscoelastic secretion, covering the epithelia surfaces of several body tracts. Its function and composition differ at different locations, but its general task is to protect tissues from dehydration, mechanical stress, and to act as barrier against microorganisms and toxic substances. Mucus is mainly composed of water, lipids, small proteins and nucleic acids, but its...
Fluorescent proteins (FPs) have revolutionized the imaging technologies in biological science. A better understanding of the structure and function for FPs will help to develop new molecular designs to generate further practical devices. Recently, we reported neutron structural analysis of the green fluorescent protein (GFP) to show the characteristic protonation (deuteration) states of the...
The elucidation of the protein-protein interaction, especially among membrane proteins and protein complexes, is one of the most important research fields in life science. Such proteins have large molecular weights, and the lattice lengths of their crystals have large values. Cold neutrons contribute to improve the difficulty in separating Bragg peaks from those crystals. JRR-3 has three cold...
Lactoferrin (Lf) is a non-heme protein known for its ability to naturally bind tightly Fe3+ ions in various physiological environments. Therefore, Lf has a significant role in the processes of iron regulation at the cellular level and organize the specific and non-specific immune response in the body.
The conformational changes within the protein structure caused by the iron-binding are...
The protein-protein interactions, namely those between the cationic lactoferrin and the oppositely charged β-lactoglobulin have been the subject of many studies due to their appeal for different food and pharmaceutical applications. These two proteins show some peculiarities in terms of physicochemical properties and behaviour in solutions. Although the hetero-complexation of the proteins is...
The highly penetrative and non-ionizing nature of neutrons can provide an ideal probe of structure and dynamics in cellular systems in a near physiological context. While many cellular systems can be quite complex the red blood cell (RBC) provides a simple system in which useful quantitative information can be extracted. Investigations with SANS [1] and QENS [2] from cell suspensions and...
Despite of the pivotal role that hydrogen (H) atoms play in protein biological function, and the fact these comprise approximately 50% of all protein atoms, their observation through X-ray diffraction remains elusive. Conversely, neutron diffraction data at resolutions better than 2.5 Å allows the determination of H positions, providing unique insight to the catalytic mechanisms of enzymes....
Infrared spectroscopy serves as local probe reporting on specific vibrations in some side chains which are spectrally distant from the complicated infrared spectrum of a protein in solution. Here, infrared spectroscopy can give information on the fold of the protein and also follow aggregation phenomena. Small angle neutron scattering also reports on the global structure of proteins in...
PcyA reduces biliverdin IXα (BV), a heme degradation product, in a ferredoxin-dependent manner, to synthesize phycocyanobilin, which plays an important role in photosynthesis and biological photoresponse. PcyA is a unique enzyme that sequentially reduces D-ring vinyl group and A-ring vinyl group of BV in a site-specific manner. In this study, Ile86 located near the important amino acid Asp105,...
The self-assembly of biological amphiphilic molecules, lipids, into lamellar structures, forms the basis of a selective transport barrier around the cell cytoplasm, the lipid bilayer. Neutron diffraction, when combined with molecular deuteration, provides an important high resolution tool in the understanding the localization of molecules in this structure. This paradigm, a description of...
Structural changes at the intra- and interchain level induced by the phase transition of poly(N-isopropylacryl amide) (PNIPAM) can be tracked in real-time by time-resolved small-angle neutron scattering (tr-SANS). PNIPAM is one of the most commonly and extensively studied thermoresponsive polymer due to lower critical solution temperature (LCST) in water that occurs at the physiologically...
TOFTOF is a direct geometry disc-chopper time-of-flight spectrometer. A cascade of seven fast rotating disc choppers is used to prepare a monochromatic pulsed beam which is focussed onto the sample by a converging super-mirror section. The scattered neutrons are detected by 1000 3He detector tubes with a time resolution up to 50 ns. The detectors are mounted at a distance of 4 m and cover 12...
We have investigated the impact of the drugs benzocaine and propanolol on a lipid bilayer formed by L-alpha-phosphatidylcholine. The methods used were neutron reflectivity, grazing incidence small angle neutron scattering, small and ultra small angle neutron scattering. On the one hand, we observed a membrane stiffening and a stalk formation for benzocaine. On the other hand, disordered...
The Myelin Basic Protein (MBP) is an essential part of the myelin sheath in almost all vertebrates and, thus, contributes significantly to flawless signal conduction. Here, one of its key properties is the ability to perform a Liquid-Liquid Phase Separation (LLPS), the coexistence of highly concentrated protein phases within a diluted solution.
Microscopy experiments have indicated that a...
Chlorite dismutases (Clds), are heme b-dependent oxidoreductases that are catalysing the degradation of toxic chlorite to harmless chloride and molecular oxygen. This catalytic function turns Clds into interesting enzymes for bioremediation. The enzyme CCld (from Cyanothece sp. PCC7425) was studied extensively with regard to its biochemical and biophysical properties and represents a perfectly...
The outbreak of the coronavirus disease (COVID-19) caused by the coronavirus SARS-CoV-2 spread to every continent affecting the global health and economy. The first two open reading frame of the SARS-CoV-2 genome are translated into two polyproteins.These are cleaved into 16 non-structural proteins (nsp1-nsp16), which are essential for viral replication and transcription [1].Among these,...
