21 research outputs found
Лингвокультурная специфика представления российско-вьетнамских отношений в русскоязычном новостном интернет-дискурсе
Настоящее исследование посвящено описанию лингвокультурной специфики представления российско-вьетнамских отношений в новостном дискурсе. В работе рассматриваются основные аспекты взаимодействия между странами, отраженные в новостных текстах, и средства их репрезентации. В результате проведенного исследования устанавливаются значимые для формирования образа «своей» и «чужой» страны понятия и способы их объективации в языке СМИ.The present study is devoted to the description of the linguocultural particularities of the presentation of Russian-Vietnamese relations in news discourse. The paper studies the main aspects of cooperation between the two countries, reflected in news texts and its means of representation. As a result of the recent study, significant notions and methods of objectification in media’s language are stated for the formation of images of “our” and “their” country
Modeling molecular crystals formed by spin-active metal complexes by atom-atom potentials
We apply the atom-atom potentials to molecular crystals of iron (II)
complexes with bulky organic ligands. The crystals under study are formed by
low-spin or high-spin molecules of Fe(phen)(NCS) (phen =
1,10-phenanthroline), Fe(btz)(NCS) (btz = 5,5,6,6-tetrahydro-4\textit{H},4\textit{H}-2,2-bi-1,3-thiazine), and Fe(bpz)(bipy) (bpz =
dihydrobis(1-pyrazolil)borate, and bipy = 2,2-bipyridine). All
molecular geometries are taken from the X-ray experimental data and assumed to
be frozen. The unit cell dimensions and angles, positions of the centers of
masses of molecules, and the orientations of molecules corresponding to the
minimum energy at 1 atm and 1 GPa are calculated. The optimized crystal
structures are in a good agreement with the experimental data. Sources of the
residual discrepancies between the calculated and experimental structures are
discussed. The intermolecular contributions to the enthalpy of the spin
transitions are found to be comparable with its total experimental values. It
demonstrates that the method of atom-atom potentials is very useful for
modeling organometalic crystals undergoing the spin transitions
Computational IR Spectroscopy of Insulin Dimer Structure and Conformational Heterogeneity
We have investigated the structure and conformational dynamics of insulin dimer using a Markov state model (MSM) built from extensive unbiased atomistic MD simulations, and performed infrared spectral simulations of the insulin MSM to describe how structural variation within the dimer can be experimentally resolved. Our model reveals two significant conformations to the dimer: a dominant native state consistent with other experimental structures of the dimer, and a twisted state with a structure that appears to reflect a ~55° clockwise rotation of the native dimer interface. The twisted state primarily influences the contacts involving the C-terminus of insulin’s B chain, shifting the registry of its intermolecular hydrogen bonds and reorganizing its sidechain packing. The MSM kinetics predict that these configurations exchange on a 14 μs timescale, largely passing through two Markov states with a solvated dimer interface. Computational amide I spectroscopy of site-specifically 13C18O labeled amides indicates that the native and twisted conformation can be distinguished through a series of single and dual labels involving the B24F, B25F, and B26Y residues. Additional structural heterogeneity and disorder is observed within the native and twisted states, and amide I spectroscopy can also be used to gain insight into this variation. This study will provide important interpretive tools for IR spectroscopic investigations of insulin structure, and transient IR kinetics experiments studying the conformational dynamics of insulin dimer.</div
Optimal Number of Coarse-Grained Sites in Different Components of Large Biomolecular Complexes
The computational study of large biomolecular complexes
(molecular
machines, cytoskeletal filaments, etc.) is a formidable challenge
facing computational biophysics and biology. To achieve biologically
relevant length and time scales, coarse-grained (CG) models of such
complexes usually must be built and employed. One of the important
early stages in this approach is to determine an optimal number of
CG sites in different constituents of a complex. This work presents
a systematic approach to this problem. First, a universal scaling
law is derived and numerically corroborated for the intensity of the
intrasite (intradomain) thermal fluctuations as a function of the
number of CG sites. Second, this result is used for derivation of
the criterion for the optimal number of CG sites in different parts
of a large multibiomolecule complex. In the zeroth-order approximation,
this approach validates the empirical rule of taking one CG site per
fixed number of atoms or residues in each biomolecule, previously
widely used for smaller systems (e.g., individual biomolecules). The
first-order corrections to this rule are derived and numerically checked
by the case studies of the Escherichia coli ribosome and Arp2/3 actin filament junction. In different ribosomal
proteins, the optimal number of amino acids per CG site is shown to
differ by a factor of 3.5, and an even wider spread may exist in other
large biomolecular complexes. Therefore, the method proposed in this
paper is valuable for the optimal construction of CG models of such
complexes