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DC Electrical Conductivity in Studies on Solid-State Proteins

100%
Kubisz L., Hojan-Jezierska D.
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issue 1
103-105
EN
In structural studies on biological materials, among other methods, electrical techniques are used widely. Temperature dependence of electrical conductivity is a method permitting studies on denaturation, glass transition and water release - processes, which occur in solid-state proteins. Variations of amplitude and temperature of the peak on the recorded thermogram make it possible to draw conclusions about thermal stability and physicochemical processes occurring in the studied biological material. The shape of experimental curve is material-related and depends upon its "history". The paper is based on experimental results obtained mainly for collagen.
2
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The Increase in Protein Contour Length Depends on Mechanical Unfolding Conditions

100%
Dąbrowska A., Lebed K., Lekka M., Kulik A., Forró L.
Acta Physica Polonica A
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2008
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vol. 113
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issue 2
753-762
EN
Many proteins in alive organisms have a domain structure providing them the possibility to reversible unfolding, which seems to play an essential role in those processes occurring in tissues which are controlled by mechanical cellular tension. In this work the atomic force microscopy was applied to investigate the mechanical properties of the single molecules of fibronectin, a protein participating in the important mechanical processes in extracellular matrix. The results showed that the conditions of mechanical stretching influence not only the force required to unfolding of a domain but also the increase in protein contour length induced by such unfolding event. Two mean values of the increase in length (called shortly the unfolding length) L_1 and L_2, were obtained and ascribed to unfolding of either the whole fibronectin domain of type III (L_2) or its fragment (L_1). Both unfolding lengths revealed similar dependence on the stretching conditions. This experimental observation of increase in unfolding length with increasing loading rate was successfully described with a combination of two theoretical models (Bell model and the worm-like-chain model), previously used separately in the analysis of protein unfolding. The general mechanical property of fibronectin domains was emphasized and proposed as a potential determinant of the cellular adhesion.
3
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Design of a 5-Station Macromolecular Crystallography Beamline at MAX-Lab

100%
Mammen C., Ursby T., Cerenius Y., Thunnissen M., Als-Nielsen J., Larsen S., Liljas A.
Acta Physica Polonica A
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2002
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vol. 101
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issue 5
595-602
EN
A beamline for macromolecular crystallography is under construction at the Swedish synchrotron light source MAX-lab at Lund University in a collaborative effort between Denmark and Sweden. Of the 7 mrad horizontal wiggler fan emitted from the new superconducting multipole wiggler, the central 2 mrad will be used and split in three parts. The central 1 mrad will be used for a tunable station optimised for multi-wavelength anomalous diffraction experiments and on each side of the central fan there will be two fixed wavelength stations using different energies of the same part of the beam. These in total five stations can be used simultaneously and independently for collecting diffraction data.
4
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Protein Structure and Function in the Time-Domain of Vibrational Spectroscopies. The Promising Applications of IR Synchrotron Radiation Micro-Spectroscopy

88%
Marcelli A.
Acta Physica Polonica A
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2006
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vol. 109
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issue 3
287-304
EN
Fourier Transform Infrared (FTIR) spectroscopy is a fundamental technique capable to characterize proteins and to investigate their conformation and dynamics in real physiological environments. Actually, a FTIR spectrum is characterized by many features, which may be correlated to the different components of the protein structure. In the last decade many relevant results have been achieved with this technique in terms of chemical imaging of proteins at subcellular level and in the investigation of cooperative phenomena. This contribution presents a few examples that illustrate the capability of the FTIR spectroscopy to investigate both protein structure and function and the opportunities offered by IR synchrotron radiation sources. Indeed the high source brilliance of these sources enables FTIR micro-spectroscopy to be performed with spatial and time resolution not available with standard sources. Moreover, the combination of synchrotron radiation and new two-dimensional detectors open new opportunities to investigate in the IR energy domain different protein processes in real time and with proteins in their native environments.
5
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Infrared Synchrotron Radiation: from Condensed Matter to Biology Researches

88%
Marcelli A., Iliescu C.
Acta Physica Polonica A
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2001
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vol. 100
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issue 5
647-658
EN
Infrared spectroscopy is probably the oldest spectroscopic method applied to investigate materials and chemico-physical phenomena. Nowadays, infrared spectroscopy represents the characterization technique most applied in the industry and in many technological processes. In the last decades a significant progress has been achieved in the use of the intense and brilliant infrared emission from electron storage rings previously used only as VUV and X-ray sources. In the infrared range the low energy of the electron beam does not affect the synchrotron radiation spectral distribution, while high current will make storage rings the most brilliant infrared sources to be used for infrared spectroscopy and micro-spectroscopy. Infrared micro-spectroscopy is a unique technique that combines microscopy and spectroscopy for purposes of micro-analysis. Spatial resolution, within a microscopic field of view, is the goal of the modern infrared micro-spectroscopy applied to condensed matter physics, materials science, biophysics, and now to medicine. Although limited in spatial resolution, infrared is able to resolve chemistry using the contrast of the absorption lines. Fourier transform-infrared micro-spectroscopy using synchrotron radiation is now able to collect data with 2-4 cm^{-1} resolution on the scale of 10-100 seconds up to an area of a few microns opening a new scenario: infrared spectroscopy of entire cells and tissue. Moreover, distributions of functional groups such as proteins, lipids, and nucleic acids can be achieved inside a single living cell with a spatial resolution of a few microns.
6
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Lysozyme Amyloid Fibrils Doped by Carbon Nanotubes

88%
Majorošová J., Tomašovičová N., Mitróová Z., Rajňák M., Girman V., Kopčanský P.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
588-590
EN
Production of new composites for the creation of modern materials with desired properties is the key feature of nanotechnology. Despite the well known advantages of magnetic nanoparticles, the aim of the present study was to synthesize lysozyme amyloid fibrils from hen egg white and subsequently doped this solution with single walled carbon nanotubes and with the magnetite Fe₃O₄ labelled single walled carbon nanotubes. Transmission electron microscopy and polarization optical microscopy were used to obtain the structural and dimensional information about samples. Measurements of magnetic properties indicate the considerable increase of the saturation magnetization for solutions included the magnetite nanoparticles.
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