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91.
Xiang L Ishii T Hosoda K Kamiya A Enomoto M Nameki N Inoue Y Kubota K Kohno T Wakamatsu K 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2008,194(1):147-151
Prevention of aggregation is critical for analyzing protein structure. Non-detergent sulfobetaines (NDSBs) are known to prevent protein aggregation, but the molecular mechanisms of their anti-aggregation effect are poorly understood. To elucidate the underlying mechanisms, we analyzed the effects of dimethylethylammonium propane sulfonate (NDSB-195) on acidic fibroblast growth factor (aFGF). NDSB-195 (0.5M) increased both aggregation and denaturation temperatures of aFGF by 4 degrees C. Chemical shift perturbation analyses indicated that many affected residues were located at the junction between a beta-strand (or 3(10)-helix) and a loop, irrespective of the chemical properties of the residue. The apparent dissociation constants of the interaction ranged from 0.04 to 3M, indicating weak interactions between NDSB and protein molecules. 相似文献
92.
Takahiro Yonezawa Tatsuya Murakami Koichi Higashimine Antoine Fleurence Yoshifumi Oshima Yukiko Yamada-Takamura 《Surface and interface analysis : SIA》2019,51(1):95-99
Layered materials can be grown on various substrates through van der Waals epitaxy (vdWE) regardless of lattice mismatch. The atomistic study of the film-substrate interface in vdWE is becoming increasingly important due to their expected applications as two-dimensional (2D) materials. In this contribution, we have grown GaSe thin films on Ge(111) substrates by molecular beam epitaxy and studied the GaSe/Ge(111) interface using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Cross-sectional HAADF-STEM observations revealed that the grown layers adopt predominantly the expected wurtzite-like structure and stacking, but layers with zinc-blende-like structure, similar to Ga2Se3 but apparently different, and other layer stacking sequences, exist locally near the film-substrate interface. These results demonstrate that even in vdWE, structural changes can occur in the grown layers adjacent to the substrate, highlighting the importance of such interface for synthesizing and applying ultimately thin 2D materials. 相似文献
93.
Gert-Jan Bekker Mitsugu Araki Kanji Oshima Yasushi Okuno Narutoshi Kamiya 《Journal of computational chemistry》2020,41(17):1606-1615
Multicanonical molecular dynamics based dynamic docking was used to exhaustively search the configurational space of an inhibitor binding to the N-terminal domain of heat-shock protein 90 (Hsp90). The obtained structures at 300 K cover a wide structural ensemble, with the top two clusters ranked by their free energy coinciding with the native binding site. The representative structure of the most stable cluster reproduced the experimental binding configuration, but an interesting conformational change in Hsp90 could be observed. The combined effects of solvation and ligand binding shift the equilibrium from a preferred loop-in conformation in the unbound state to an α-helical one in the bound state for the flexible lid region of Hsp90. Thus, our dynamic docking method is effective at predicting the native binding site while exhaustively sampling a wide configurational space, modulating the protein structure upon binding. 相似文献
94.
Kinetics of hydration of CaO---Al2O3---P2O5 and Na2O---CaO---B2O3---Al2O3 glasses in an autoclave at high temperatures and high pressures has been investigated. The hydration of the phosphate glasses may occur as a result of hydrolysis of glass constituents to form orthophosphate crystals. Cabal glasses which do not contain any alkali oxides have shown a quite high resistance to water. Substitution of sodium for calcium deteriorates the chemical durability of Cabal glasses. 相似文献
95.
Iwasaki T Maegawa Y Hayashi Y Ohshima T Mashima K 《The Journal of organic chemistry》2008,73(13):5147-5150
A new catalytic transesterification promoted by a tetranuclear zinc cluster was developed. The mild reaction conditions enabled the reactions of various functionalized substrates to proceed in good to high yield. A large-scale reaction under solvent-free conditions proceeded with a low E-factor value (0.66), indicating the high environmental and economical advantage of the present catalysis. 相似文献
96.
The diastereoselective construction of stereotriads having consecutive methyl, hydroxy, and methyl substituents was realized by the substrate-controlled crotylation of beta-branched alpha-methylaldehydes with potassium crotyltrifluoroborates. Especially, crotylation of 2-(1,3-dithian-2-yl)propanal with potassium ( E)-crotyltrifluoroborate afforded, in good yield and with excellent diastereoselectivity, a useful building block that has different and potential functional groups on both ends. 相似文献
97.
Iijima M Yoshimura M Tsuchiya T Tsukada M Ichikawa H Fukumori Y Kamiya H 《Langmuir : the ACS journal of surfaces and colloids》2008,24(8):3987-3992
A novel thermo- and pH-sensitive nanogel particle, which is a core-shell structured particle with a poly(N-isopropylacrylamide) (p(NIPAAm)) hydrogel core and a poly(ethylene glycol) monomethacrylate grafted poly(methacrylic acid) (p(MMA-g-EG)) shell, is of interest as a vehicle for the controlled release of peptide drugs. The interactions between such nanogel particles and artificial mucin layers during both approach and separation were successfully measured by using colloid probe atomic force microscopy (AFM) under various compression forces, scan velocities, and pH values. While the magnitudes of the compression forces and scan velocities did not affect the interactions during the approach process, the adhesive force during the separation process increased with these parameters. The pH values significantly influenced the interactions between the nanogel particles and a mucin layer. A large steric repulsive force and a long-range adhesive force were measured at neutral pH due to the swollen p(MMA-g-EG) shell. On the other hand, at low pH values, the steric repulsive force disappeared and a short-range adhesive force was detected, which resulted from the collapse of the shell layer. The nanogel particles possessed a pH response that was sufficient to protect the incorporated peptide drug under the harsh acidic conditions in the stomach and to effectively adhere to the mucin layer of the small intestine, where the pH is neutral. The relationships among the nanogel particle-mucin layer interactions, pH conditions, scan velocities, and compression forces were systemically investigated and discussed. 相似文献
98.
Nojima H Takeda-Shitaka M Kanou K Kamiya K Umeyama H 《Chemical & pharmaceutical bulletin》2008,56(5):635-641
Class I major histocompatibility complex (MHC) molecules have three domains, a platform domain and two membrane-proximal immunoglobulin-like domains, an alpha3 domain and a beta2-immunoglobulin (beta2m). To understand the dynamic interactions among the three domains, we simulated the behavior of a partial model deficient in beta2m and another model deficient in the alpha3 domain, by normal mode analysis. As a result, the partial model deficient in beta2m was more flexible in interdomain conformation than the other model. The lowest frequency modes (<2 cm(-1)) observed for the simulations of the partial model deficient in beta2m showed clear interdomain motions as if each domain moved like a rigid body. Such low frequencies and clear interdomain motions were not observed for the simulations of the other model, therefore the interdomain flexibility of the partial model deficient in beta2m may be due to the lowest frequency modes (<2 cm(-1)). These results suggest that beta2m contributes to maintaining the interdomain conformation of class I MHC molecules more than the alpha3 domain does, and may offer convincing evidence to support the notion that the alpha3 domain and beta2m do not have an equal influence on the structural stability of class I MHC molecules. 相似文献
99.
Inumaru K Ishihara T Kamiya Y Okuhara T Yamanaka S 《Angewandte Chemie (International ed. in English)》2007,46(40):7625-7628
100.
Kanaoka S Yagi N Fukuyama Y Aoshima S Tsunoyama H Tsukuda T Sakurai H 《Journal of the American Chemical Society》2007,129(40):12060-12061