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127 citations found for Hasegawa,

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Full-length human tau-protein kinase I (TPK-I; also known as glycogen synthase kinase-3[beta], GSK-3[beta]) was produced in E. coli and crystallized. The crystals diffract up to 2.3 Å resolution and belong to the orthorhombic space group P2_12_12_1, with unit-cell parameters a = 82.9, b = 86.1, c = 178.1 Å measured at 100 K.

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The first two crystal structures of binary complexes of full-length glycogen synthase kinase 3[beta] with the ATP analogues hydrolysate ADP and AMPPNP are described. Although several other crystal structures of the enzyme have already been reported, none of them contain ATP analogues. The structures of these binary complexes reveal detailed features of nucleotide recognition by GSK3[beta] and may have useful implications in the design of drug candidates against Alzheimer's disease.

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A dimeric analogue of desoxazoline ascidiacycl­amide was synthesized to increase the conformational flexibility of the mol­ecule. The overall structure of this compound, C72H112N16O16S4·3C3H7NO·H2O, was relatively flat and was classified neither as the folded nor squared form, which have been observed in ascidiacycl­amide analogues. Rather, a unique [beta]-sheet was formed in the 48-membered ring with pseudo-twofold symmetry. This was stabilized by hydrogen bonds including C-H...O interactions between thia­zole and carbonyl O atoms. This is the first structure of an ascidiacycl­amide analogue to exhibit a flat conformation composed of a [beta]-sheet.

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Ascidiacycl­amide, cyclo(-Ile-Oxz-D-Val-Thz-)2, has two methyl-oxazoline (Oxz) residues, and each Oxz residue has two chiral C atoms. In the present work, C38H60N8O12S4, a chiral modification of these atoms was attempted. A total of ten diastereomers were considered, of which seven were synthesized. For the three remaining diastereomers, the reaction was incomplete or very much slowed down. These diastereomers had the D configuration for both Oxz residues. This result appeared to be related to the conformation of the reaction intermediates. Therefore, the intermediates were converted into stable forms and then isolated to confirm their structures. Crystals were obtained from one derivative and its structure was found to be of the folded form. In this form, the activated atoms were separated from the target atoms. It is suggested that this folded conformation hinders the completion of the reaction.

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Kynostatin {KNI-272; systematic name: 3-[3-benzyl-2-hydroxy-9-(isoquinolin-5-yl­oxy)-6-methyl­sulfanyl­methyl-5,8-dioxo-4,7-di­aza­nonanoyl]-N-tert-butyl-1,3-thia­zolane-4-carbox­amide}, a highly selective and potent HIV protease inhibitor containing allo­phenyl­norstatin [(2S,3S)-3-amino-2-hydroxy-4-phenyl­butyric acid], has been crystallized as the hydrate, C33H41N5O6S2·0.803H2O, from aqueous hexyl­ene glycol. The observed disorder of the phenyl group in the structure is related to the mode of hydration. The backbone conformation of the mol­ecule is twisted and the overall conformation of the free inhibitor is similar to that observed in its complex with HIV protease.

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Acta Cryst. (2008). A64, C593
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Acta Cryst. (2008). A64, C135-C136
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Acta Cryst. (2008). A64, C420-C421
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The lateral and vertical components of the radius of gyration for a single block copolymer chain and those of a single homopolymer chain in the lamellar microdomain space formed by a mixture of diblock copolymers and homopolymers were investigated by means of small-angle neutron scattering (SANS) and the microdomain structures by small-angle X-ray scattering (SAXS). The homopolymers whose molecular weights are much smaller than that of the corresponding chains of the block copolymers were used so that the homopolymers were uniformly solubilized in the corresponding microdomains. The SANS result suggests that the homopolymer chains in the microdomain space as well as the block copolymer chains are more compressed in the direction parallel to the interface and more stretched in the direction perpendicular to the interface than the corresponding unperturbed polymer chains with the same molecular weight. On increasing the volume fraction of the homopolymers the thickness of the lamellar microdomains increases. The block copolymer chains were found to undergo an isochoric affine deformation on addition of the homopolymers or with the change of the thickness of the lamellar microdomains.

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Acta Cryst. (2005). A61, c145
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Acta Cryst. (2011). A67, C46
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Virus-like particles (VLPs) from Norovirus Chiba strain were crystallized and data were collected to 3.2 Å resolution. X-ray analysis revealed that although 38 nm VLPs with T = 3 symmetry had been prepared for crystallization, the crystal contained 23 nm VLPs with T = 1 icosahedral symmetry.


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A shutterless continuous rotation method using an X-ray complementary metal-oxide semiconductor (CMOS) detector has been developed for high-speed, precise data collection in protein crystallography. The new method and detector were applied to the structure determination of three proteins by multi- and single-wavelength anomalous diffraction phasing and have thereby been proved to be applicable in protein crystallography.


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A new room-temperature (RT) data-collection method for microcrystals was developed by combining serial synchrotron rotation crystallography with the humid air and glue-coating method. The RT data-collection strategy for micro-crystallography was evaluated by examining the efficiency, the influence of non-isomorphism and radiation damage, and the effectiveness of increasing the number of merged images. An equation was proposed that relates the achievable resolution to the total photon flux used to obtain a data set.

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The best practice for dose-limiting serial synchrotron rotation crystallography was examined through anomalous signal and single-wavelength anomalous diffraction phasing of mercury-bound luciferin regenerating enzyme. Sample rotation enabled accurate data collection with fewer diffraction images than without rotation, and an increase in resolution and anomalous signal was observed up to 3.4 MGy even though specific damage occurred after an accumulated dose of 1.1 MGy.

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Acta Cryst. (2006). A62, s129
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Acta Cryst. (2014). A70, C331
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BL41XU is the oldest macromolecular crystallography (MX) beamline at SPring-8 [1]. Although it has been contributing to the structure determination of difficult samples since its start of operation in 1997, the targets for the structural study is still getting more challenging and the crystal quality brought to the beamline is getting worse. Therefore, we have upgraded the focusing optics and diffractometer of BL41XU to cope with these targets. Our goal is to achieve an environment which can offer a stable beam with a photon flux of >1013 photons/s in the beam size range of 5 ~ 50[mu]m. It is a complementary specification with our micro-focus beamline BL32XU [2], and allows both micro-crystallography and data collection using crystal volume. The new optics adopts a two-step focusing with elliptical figured mirrors: the first optics is a single horizontal mirror and the second one adopts Kirkpatrick-Baez (KB) configuration. At the middle of the two focusing optics, a high precision horizontal slit is installed to define secondary source size. The beam size can be changed either by changing the secondary source size, by offsetting the sample position, or by tilting the vertical mirror. For the stable use of small beam, both KB mirror and diffractometer were equipped on the granite stage, and enclosed in a booth in which the temperature is keep stable. On the new diffractometer, we equipped PILATUS3 6M that enables rapid data collection combining with high flux beam. Together with the upgrade of hardware, software tools, which support diffraction based centering and determination of measurement condition, have been implemented in order to make full use of the renewed beamline. The upgrade was conducted in the long shut-down period between January and March of this year, and the beamline was opened for users in the middle of May after commissioning of one month. The result of commissioning and initial results will be presented. This study was supported by the MEXT of Japan.

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