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51.
Srisailam S Kumar TK Srimathi T Yu C 《Journal of the American Chemical Society》2002,124(9):1884-1888
Effect(s) of organic solvents on an all beta-sheet protein are investigated to understand the influence of backbone conformation on protein aggregation. Results obtained in the present study reveal that protein aggregation is accompanied by the formation of non-native beta-sheet conformation. In contrast, induction of non-native helical segments in the protein is found to inhibit aggregation. The differential effects of the secondary structures on protein aggregation are proposed to stem from the disparity in the nature of the hydrogen bonds and packing of the side chains of hydrophobic residues in the beta-sheet and alpha-helix conformation. In our opinion, the results of the present study provide useful hints to develop methods to alleviate the problems of both in vitro and in vivo protein aggregation. 相似文献
52.
53.
M. Nilofar Nissa P. G. Aravindan V. Kasinath G. Gopalakrishnan H. Merazig D. Velmurugan 《Crystal Research and Technology》2004,39(7):643-649
The title compounds (I) and (II) crystallize in the monoclinic space group P21/c and orthorhombic space group Pbca respectively. The inter‐planar angle between the two phenyl rings are 55° in I and 24.5(1)° in II. The molecular packing of the compounds I and II are stabilized by C‐H…O and C‐H…π, and N‐H…O, C‐H…O and C‐H…π interactions, respectively. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
54.
B. Sivakumar K. SethuSankar U. P. Senthil Kumar R. Jeyaraman D. Velmurugan 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o153-o155
The title compound, C24H19N3O, crystallizes in the centrosymmetric space group P21/a with one molecule in the asymmetric unit. The tetrahydropyridine ring has a boat conformation. The dihedral angle between the fused pyridine rings is 16.2 (1)°. The equatorial and axial orientations of the two phenyl groups with respect to the tetrahydropyridine ring are confirmed. The nitroso group is coplanar with the attached C—N—C group. The interplanar angle formed between the fused tetrahydropyridine and benzene planes is 13.4 (1)°. The crystal packing is stabilized by an intermolecular C—H⃛O hydrogen bond, which forms a C(9) graph‐set chain running along the [001] direction. 相似文献
55.
K. SethuSankar S. Saravanan D. Velmurugan Masood Parvez 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o156-o158
The title compound, 4′‐methoxy‐α,2,3′,4‐tetranitrostilbene, C15H10N4O9, crystallizes in the centrosymmetric space group P21/c with one molecule in the asymmetric unit. The phenyl rings are inclined to one another and form a dihedral angle of 57.4 (1)°. The size of this angle is a result of intermolecular C—H⃛O interactions involving the phenyl H atoms. The torsion angle between the phenyl rings, −7.5 (3)°, indicates a cis geometry between them. The methoxy group is almost coplanar with the phenyl ring, and the nitro groups are twisted with respect to the phenyl rings because of the short H⃛O contacts. The crystal packing is stabilized by C—H⃛O hydrogen bonds, and the intermolecular hydrogen bonds form a C(12) graph‐set chain running along the [010] direction. 相似文献
56.
M. Yogavel P. G. Aravindan D. Velmurugan K. Sekar S. Selvi P. T. Perumal S. Shanmuga Sundara Raj H.‐K. Fun 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(7):o394-o396
In the title compounds, C13H15N3O, (I), and C13H15N3O2, (II), the dihedral angles between the planes of the phenyl ring and the amide group are 4.1 (1) and 20.7 (1)°, respectively. The molecules adopt a fully extended conformation, aided by intramolecular interactions. The molecular structures of (I) and (II) display different crystal packing and hydrogen‐bonding networks. 相似文献
57.
M. Nilofar Nissa D. Velmurugan S. Shanmuga Sundara Raj H.‐K. Fun V. Kasinath G. Gopalakrishnan 《Crystal Research and Technology》2002,37(1):125-133
The crystal structures of two cinnamanilide derivatives 2‐methyl cinnamanilide (C16 H15 N O – compound I) and 2‐methoxy cinnamanilide (C16 H15 N O2 – compound II) are reported. In both crystal structures, the cinnamamide group is almost planar. The inter‐planar angle between the two phenyl rings are 71.6(1)° for compound I and 7.5(1)° for compound II. The N‐H…O and C‐H…O type of hydrogen bond interactions between the amide group and the carbonyl group stabilizes the molecular packing as chains in the crystal lattice. 相似文献
58.
59.
Rema Krishnaswamy Hynd Remita Marianne Impéror-Clerc Catherine Even Patrick Davidson Brigitte Pansu 《Chemphyschem》2006,7(7):1510-1513
Single-crystalline platinum nanorods, monodisperse in diameter, are synthesized through a simple process at room temperature, in cetyltrimethyl ammonium bromide (CTAB) solution. The complexation of the CTA+ surfactant ion with tetrachloroplatinate in the presence of hexanol leads to the formation of a precipitate with a lamellar crystalline structure. The reduction of Pt(II) metal ions to Pt(0) is carried out using gamma radiolysis. Transmission electron microscopy (TEM) observations of the nanoparticles extracted from the solution, three weeks after radiolysis, revealed single-crystalline Pt nanorods, monodisperse in diameter (3-4 nm) and 20-60 nm long. By following the shape of the nanorods at various stages of the growth, it was found that the single-crystalline nanorods grow by coalescence of spherical seeds 3-4 nm in diameter. This suggests an aggregative mechanism similar to that recently observed for silver particles in solution. 相似文献
60.
Structures of complexes formed in aqueous solutions by some anionic polyelectrolytes (double and single stranded (ds and ss)
DNA, poly(vinyl sulfonate) (PVS), and poly(styrene sulfonate) (PSS)) with a cationic surfactant system consisting of cetyltrimethylammonium
bromide (CTAB) and sodium 3-hydroxy-2-naphthoate (SHN) have been determined using small angle X-ray diffraction. All complexes
are found to have a two-dimensional (2-D) hexagonal structure at low SHN concentrations. Analysis of the diffraction data
shows that the ds DNA—CTAB complex has an intercalated structure, with each DNA strand surrounded by three cylindrical micelles.
On increasing SHN concentration, DNA—CTAB—SHN complexes exhibit a hexagonal-to-lamellar transition, whereas PVS complexes
show a hexagonal → centered rectangular → lamellar transition. PSS complexes show yet another sequence of structures. These
results indicate the significant influence of the chemical nature of the polyelectrolyte on the structure of the complexes. 相似文献