Instrumental and methodological provision for structural SAXS/WAXS studies of biological nanosystems using synchrotron radiation
V.N.Korneev1), V.A.Shlektarev2), A.V.Zabelin3), N.F.Lanina2), B.P.Tolochko4), A.A.Vazina2)
1) Institute of Cell Biophysics, RAS, Pushchino, Russia 2) Institute of Theoretical and Experimental Biophysics, RAS, Pushchino, Russia 3) National Research Centre Kurchatov Institute, Moscow, Russia 4) Budker Institute of Nuclear Physics, SB of RAS, Novosibirsk, Russia
Until creation of synchrotron radiation (SR) sources in the Siberian and Moscow regions (VEPP-2, VEPP–3, VEPP-4, and Siberia-2), in the country there has not been instrumental and methodological basis for our research in the field of structural biology of tissues. Long-time work of our collective direct on studying the mechanisms of structural and functional stability of the native and transformed tissues of humans and animals under various physicochemical influences. Such heterogeneous multicomponent ensembles of living systems are characterized by high order with structure periods in the nanometer range of the order of 1-100 nm at extremely low concentration in native tissues and weak scattering ability.
The report discusses the instrumental and methodological developments using SR, as well as some test results of our SAXS/WAXS diffraction studies of biological nanosystems in different physiological states. X-ray stations based on monochromatic (λ=const) and energy (Θ=const) diffractometry methods were created on the working channels of SR sources. The figure shows their generalized block scheme with fundamental differences for each method in the systems of SR beam formation and registration of X-ray diffraction patterns on the basis of positional-sensitive coordinate or power-dispersion detectors. New approaches to the formation of the SR beam were implemented at the stations. So, there was carried out next operations for the method λ=const: the reversed version of the arrangement of X-ray optics of the zoom lenses based on the crystal-monochromator and polysectional mirrors; high-speed X-ray diffraction with simultaneous registration of micron periodicity of structure in visible spectrum; distantly controlled methods of combination the SR beam and object, and adjustments of the station at minimal background. There was performed some modifications for the method Θ=const: registration in the meridional (interval 0-50 mrad) and sagittal (interval 0-25 mrad) directions at 5x10-2 mrad accuracy; collimating device with mirror zoom lens; cooling of object and its scanning. These modifications allowed increasing the signal-to-noise ratio by 6-7 times.