NMR Derived Model of GTPase Effector Domain (GED) Self Association: Relevance to Dynamin Assembly

Self-association of dynamin to form spiral structures around lipidic vesicles during endocytosis is largely mediated by its ‘coiled coil’ GTPase Effector Domain (GED), which, in vitro, self-associates into huge helical assemblies. Residue-level structural characterizations of these assemblies and understanding the process of association have remained a challenge. It is also impossible to get folded monomers in the solution phase. In this context, we have developed here a strategy to probe the self-association of GED by first dissociating the assembly using Dimethyl Sulfoxide (DMSO) and then systematically monitoring the refolding into helix and concomitant re-association using NMR spectroscopy, as DMSO concentration is progressively reduced. The short segment, Arg109 - Met116, acts as the nucleation site for helix formation and self-association. Hydrophobic and complementary charge interactions on the surfaces drive self-association, as the helices elongate in both the directions resulting in an antiparallel stack. A small N-terminal segment remains floppy in the assembly. Following these and other published results on inter-domain interactions, we have proposed a plausible mode of dynamin self assembly

Способы перевода аббревиатур и сокращений в области компьютерных технологий (на примере русского и немецкого языков)

Выпускная квалификационная работа 75 с., 2 главы, 42 источника. Предмет исследования: способы перевода аббревиатур и сокращений в области компьютерных технологий с немецкого языка на русский язык. Объектом исследования: аббревиатуры и сокращения, относящиеся к области компьютерных технологий. Цель работы: выявить эффективные способы перевода аббревиатур и сокращений в области компьютерных технологий с немецкого языка на русский. Результаты исследования: были сформулированы особенности перевода аббревиатур и сокращений в области компьютерных технологий Степень внедрения/апробация работы: Было опубликовано две статьи Область применения: лингвистика, языкознание, переводоведение.Graduation thesis: 75 pg., 2 chapters, 42 resources. Subject of research: translation methods of acronyms and reductions in the field of computer technology from German into Russian. Object of research: Acronyms and reductions in the field of computer technology. Purpose of research: : to identify the translation methods of acronyms and reductions in the field of computer technology from German into Russian. Results of research: The features of the translation of acronyms and reductions in the area of computer technology has been revealed. Degree of implementation /work approbation: two articles were published. Field of application: Linguistic, theory of translatio

The dynamin middle domain is critical for tetramerization and higher-order self-assembly

The large multidomain GTPase dynamin self-assembles around the necks of deeply invaginated coated pits at the plasma membrane and catalyzes vesicle scission by mechanisms that are not yet completely understood. Although a structural role for the ‘middle' domain in dynamin function has been suggested, it has not been experimentally established. Furthermore, it is not clear whether this putative function pertains to dynamin structure in the unassembled state or to its higher-order self-assembly or both. Here, we demonstrate that two mutations in this domain, R361S and R399A, disrupt the tetrameric structure of dynamin in the unassembled state and impair its ability to stably bind to and nucleate higher-order self-assembly on membranes. Consequently, these mutations also impair dynamin's assembly-dependent stimulated GTPase activity

Structure of a mitochondrial fission dynamin in the closed conformation

Dynamin 1-like proteins (DNM1-L) are mechanochemical GTPases that induce membrane fission in mitochondria and peroxisomes. Their mechanism depends on conformational changes driven by nucleotide and lipid cycling. Here we show the crystal structure of a mitochondrial fission dynamin (CmDnm1) from the algae Cyanidioschyzon merolae. Unlike other eukaryotic dynamin structures, CmDnm1 is in a hinge 1 closed conformation, with the GTPase domain compacted against the stalk. Within the crystal, CmDnm1 packs as a diamond-shaped tetramer that is consistent with an inactive off-membrane state. Crosslinking, photoinduced electron transfer assays, and electron microscopy verify these structures. In vitro, CmDnm1 forms concentration-dependent rings and protein–lipid tubes reminiscent of DNM1-L and classical dynamin with hinge 1 open. Our data provides a mechanism for filament collapse and membrane release that may extend to other dynamin family members. Additionally, hinge 1 closing may represent a key conformational change that contributes to membrane fission