Lipidic cubic phase (LCP) has been widely recognized as a promising membrane-mimicking matrix for biophysical studies of membrane proteins and their crystallization in a lipidic environment. Application of this material to a wide variety of membrane proteins, however, is hindered due to a limited number of available host lipids, mostly monoacylglycerols (MAGs). Here, we designed, synthesized and characterized a series of chemically stable lipids resistant to hydrolysis, with properties complementary to the widely used MAGs. In order to assess their potential to serve as host lipids for crystallization, we characterized the phase properties and lattice parameters of mesophases made of two most promising lipids at a variety of different conditions by polarized light microscopy and small-angle X-ray scattering. Both lipids showed remarkable chemical stability and an extended LCP region in the phase diagram covering a wide range of temperatures down to 4 °C. One of these lipids has been used for crystallization and structure determination of a prototypical membrane protein bacteriorhodopsin at 4 °C and 20 °C.

This is a review of relevant Raman spectroscopy (RS) techniques and their use in structural biology, biophysics, cells, and tissues imaging towards development of various medical diagnostic tools, drug design, and other medical applications. Classical and contemporary structural studies of different water-soluble and membrane proteins, DNA, RNA, and their interactions and behavior in different systems were analyzed in terms of applicability of RS techniques and their complementarity to other corresponding methods. We show that RS is a powerful method that links the fundamental structural biology and its medical applications in cancer, cardiovascular, neurodegenerative, atherosclerotic, and other diseases. In particular, the key roles of RS in modern technologies of structure-based drug design are the detection and imaging of membrane protein microcrystals with the help of coherent anti-Stokes Raman scattering (CARS), which would help to further the development of protein structural crystallography and would result in a number of novel high-resolution structures of membrane proteins—drug targets; and, structural studies of photoactive membrane proteins (rhodopsins, photoreceptors, etc.) for the development of new optogenetic tools. Physical background and biomedical applications of spontaneous, stimulated, resonant, and surface- and tip-enhanced RS are also discussed. All of these techniques have been extensively developed during recent several decades. A number of interesting applications of CARS, resonant, and surface-enhanced Raman spectroscopy methods are also discussed.

Abstract. Using a multidetector system on the YuMO spectrometer allows shortening the time of measurements. The quantitative comparison of the measurement time using one and twodetector mode is done. The time range for experiments was from several minutes up to 12 hours. It was shown that two-detector system shortens more than twice the time of the measurement. While making a structural investigation using advanced software the twodetector system allows to treat the data at a qualitatively new level. An example illustrating the features of the channels choice and measurement time on the spectrometer was shown. The results of this paper could be used when planning the experiments on the YuMO spectrometer, for modernization of the installation and for equipment using time-of-flight method.

Membrane integral ATP synthases produce adenosine triphosphate, the universal “energy currency” of most organisms. However, important details of proton driven energy conversion are still unknown. We present the first high-resolution structure (2.3 Å) of the in meso crystallized c-ring of 14 subunits from spinach chloroplasts. The structure reveals molecular mechanisms of intersubunit contacts in the c14-ring, and it shows additional electron densities inside the c-ring which form circles parallel to the membrane plane. Similar densities were found in all known high-resolution structures of c-rings of F1FO ATP synthases from archaea and bacteria to eukaryotes. The densities might originate from isoprenoid quinones (such as coenzyme Q in mitochondria and plastoquinone in chloroplasts) that is consistent with differential UV-Vis spectroscopy of the c-ring samples, unusually large distance between polar/apolar interfaces inside the c-ring and universality among different species. Although additional experiments are required to verify this hypothesis, coenzyme Q and its analogues known as electron carriers of bioenergetic chains may be universal cofactors of ATP synthases, stabilizing c-ring and prevent ion leakage through it.