著者
古谷野 哲夫
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.56, no.5, pp.319-322, 2014-10-31 (Released:2014-10-31)
参考文献数
6
被引用文献数
1

Chocolate consists of solid particles such as cocoa, sugar, and milk solids which are dispersed in a continuous fat phase. The major fat in chocolate is cocoa butter, and it is crystallized at room temperature, so chocolate is a food which we eat crystals. Therefore, fat crystals play a great role in chocolate quality and storage stability. In this paper, polymorphism of cocoa butter and the transformation of polymorphic forms are reviewed including recent results.
著者
大橋 裕二
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.57, no.2, pp.131-133, 2015-04-30 (Released:2015-04-30)
参考文献数
17
被引用文献数
1

76 0 0 0 OA 学術会議の改革

著者
郷 信広
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.45, no.5, pp.341-343, 2003-10-29 (Released:2010-09-30)
参考文献数
4
著者
中根 崇智
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.64, no.2, pp.125-131, 2022-05-31 (Released:2022-06-01)
参考文献数
16

The past decade has seen revolutionary progress in single particle analysis with cryo-electron microscopes. Steady improvement in resolution has culminated in the reports of atomic resolution(1.2 Å)structures of apoferritin in 2020. This review, as a follow-up to my previous review in 2018, summarizes hardware and software improvements that enabled this milestone achievement. A quantitative analysis of the relationship between the number of particles and the resolution is presented and its practical implication in data collection strategies is discussed.
著者
志甫谷 渉
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.62, no.3, pp.143-149, 2020-08-31 (Released:2020-09-03)
参考文献数
10

Endothelin receptors(ETA and ETB)are G-protein-coupled receptors activated by endothelin-1 and are involved in blood pressure regulation. Using the microfocus beamline BL32XU at SPring-8, we determined 8 crystal structures of human ETB receptor, revealing the drug binding modes and receptor activation mechanism.
著者
中根 崇智
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.60, no.5-6, pp.230-232, 2018-12-15 (Released:2018-12-19)
参考文献数
9
著者
安達 成彦
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.63, no.4, pp.267-272, 2021-12-15 (Released:2021-12-18)
参考文献数
11

In March 2018, KEK obtained a 200 kV cryogenic electron microscopy(cryo-EM; a Talos Arctica G2 with a Falcon 3EC direct electron detector)and prepared a pipeline for solving high-resolution structures of macromolecular biomolecules, such as proteins, DNA, and RNA. In October 2018, the cryo-EM facility in KEK opened to academic and industrial users. Our mission is three-fold:to provide cryo-EM machine time for external users, to support grid-prep and data collection(and single particle analysis, if needed), and to help users acquire cryo-EM skills. One remarkable result is the single-particle analysis of an 860-kDa enzyme at 2.05 angstrom resolution, which suggested that we had established a proper protocol for cryo-EM operation and single-particle analysis. We will continue to support external users and carry out cryo-EM single particle analysis of macromolecular biomolecules.
著者
坂部 知平
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.61, no.2, pp.138-140, 2019-05-31 (Released:2019-06-05)
参考文献数
4
著者
竹田 一旗 丹羽 智美 三木 邦夫
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.57, no.2, pp.104-109, 2015-04-30 (Released:2015-04-30)
参考文献数
18

For efficient use of sunlight, the light-harvesting core antenna (LH1) and the reaction center (RC) form a supramolecular complex (LH1-RC) in photosynthetic bacteria. We determined the crystal structure of a LH1-RC complex from a purple bacterium, Thermochromatium tepidum. The structure reveals that the RC is completely surrounded by 16 αβ-heterodimers. Calcium ions are bound at the periplasmic side of LH1. 32 bacteriochlorophyll and 16 spirilloxanthin molecules form an elliptical assembly in LH1. The pigment geometry involved in the absorption characteristics and excitation energy transfer is determined. In addition, ubiquinone channels and lipid molecules are observed in the complex.
著者
中川 敦史
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.35, no.5, pp.327-333, 1993-10-25 (Released:2010-09-30)
参考文献数
21
被引用文献数
3 5

Flower colors, from red through purple to blue, are mostly from anthocyanins. Although there are many colors, only a few anthocyanins are found. We have succeeded to solve the structure of real anthocyanin and a sugar containing flavonoid, Cd-commelinin, using the Weissenberg camera for macromolecular crystallography with imaging plates at the Photon Factory. The blue flower-color development and the stability of the color can be explained by metal complexation of anthocyanin and intermolecular hydrophobic association. Commelinin is a new type of stoichiometric supramolecule, which consists of low molecular mass components.
著者
今崎 剛 高木 雄一郎
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.54, no.5, pp.292-299, 2012-10-31 (Released:2012-11-06)
参考文献数
13

Deciphering structures of the multi-protein complexes is vital to understand biology. However, the large size, complexity, heterogeneity, and typically low abundance in their native sources, have often precluded successful structural analysis of the multi-protein machines. We have determined the crystal structure of the Mediator Head module (7 subunits, 223 kDa), an essential component in RNA polymerase II transcription. Our success depended on addressing series of challenges unique to structure determination of multi-protein complexes. We anticipate that our approach will serve as a paradigm for structural analysis of the eukaryotic multi-protein complexes that regulate vital cellular processes in the future.
著者
山下 恵太郎
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.64, no.2, pp.118-124, 2022-05-31 (Released:2022-06-01)
参考文献数
15

Atomic model refinement and map calculation methods for cryo-EM single particle analysis(SPA)are explained in relation to X-ray crystallography. To make the best use of high-resolution reconstructions from SPA, it is important to calculate interpretable density maps to help build atomic models, and to use all experimental information to refine models. We developed a new program Servalcat to facilitate the structure refinement in reciprocal space. Servalcat performs structure refinement using REFMAC5, followed by calculation of weighted and sharpened Fo and Fo-Fc maps, which are useful in manual model rebuilding.
著者
冨田 研一
出版者
The Crystallographic Society of Japan
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.23, no.5, pp.289-298, 1981-09-30 (Released:2010-09-30)
参考文献数
36

The recent progress in single crystal X-ray analysis of DNA fragments involving the oligomers having alternating cytosine-guanine base sequence and novel left-handed double-stranded helical structure is reviewed and all the possible requisite conditions for providing the handedness of DNA structure are also evaluated.
著者
木下 誉富
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.59, no.4, pp.174-181, 2017-08-31 (Released:2017-08-31)
参考文献数
17
被引用文献数
1

Protein kinases transfer the γ-phosphate group of ATP to the hydroxyl group of substrate protein. 518 human kinases are classified into serine/threonine kinases and tyrosine kinases, and individually and/or synergistically transduce physiologic stimuli into cell to promote cell proliferation or apoptosis, etc. Kinases are identified as drug targets because dysfunction of kinases leads to severe diseases such as cancers. In this review, I describe structural biology on kinases and drug discovery for the severe diseases such as cancers due to kinase dysfunction.
著者
緒方 英明
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.63, no.2, pp.97-104, 2021-05-31 (Released:2021-06-05)
参考文献数
32

The metalloenzyme ‘hydrogenase’ catalyzes the reversible oxidation of dihydrogen. Crystallographic structures of[NiFe]hydrogenases from sulfate-reducing bacteria have been determined and give detailed insight into pathways for the transfer of electrons, protons and hydrogen molecules.[NiFe]hydrogenases contain one nickel and one iron in the active site, the latter carries non-protein diatomic ligands, one CO and two CN-s. A possible catalytic mechanism of the oxygen-sensitive[NiFe]hydrogenases for the heterolytic dihydrogen splitting is proposed.
著者
秋光 純 富本 晃吉
出版者
The Crystallographic Society of Japan
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.34, no.5, pp.273-282, 1992-10-30 (Released:2010-09-30)
参考文献数
26

The current status of oxide superconductors is briefly reviewed from a crystal structure perspective. Tokura et al. recently classified high-temperature superconductors using block layer concept. We propose a new “layer” concept and discuss the possibility of new block layers by reconstructing the layers. As an example, we present new high-Tc materials containing CO3 by combining an “old” and new block layers recently discovered. Finally, main roles for realizing the high-Tc superconductors are discussed from the structural point of view.
著者
吉田 徹 山田 等仁 津下 英明
出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.64, no.1, pp.69-76, 2022-02-28 (Released:2022-03-04)
参考文献数
20

The iota toxin produced by Clostridium perfringens type E is a binary toxin comprising two independent polypeptides:Ia, an ADP-ribosyltransferase, and Ib, which is involved in cell binding and translocation of Ia across the cell membrane. Binary toxin family includes C. perfringens iota toxin, C. difficile CDT, C. spiroforme CST, C. botulinum C2, and B. anthracis anthrax toxin. Here we introduce the binary toxin complex structures using single-particle Cryo-EM structural analysis and the structural basis of toxin translocation system.
著者
神山 崇
出版者
The Crystallographic Society of Japan
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.40, no.5, pp.301-307, 1998-10-31 (Released:2010-09-30)
参考文献数
17

入門講座「結晶学の原点を読む」の第2回目は, リートベルト法です.粉末回折法で構造を決定する非常に有力な手段であるリートベルト法は, 現在非常に多くの利用者がおり, 結晶学の分野では欠かせない解析法となっています.この方法の原理は非常に簡単であり, 測定された粉末回折の強度データのパターンと構造モデルから計算された強度のパターンが一致するように最小自乗法でパラメーターを求めるだけです.このように簡単な原理からなっているにもかかわらず, 計算機のプログラムは非常に複雑で多岐に渡っており, 使用している方々のほとんどにとってそのプログラムの中身はまったくブラックボックスであり, かつ出力された結果に対する吟味もどのようにしたら良いかあまりわからず使っている感があります.また, リートベルト自身によるさまざまな物質への適用例は施設報告が多く手に入りにくいものです.そのような中には, 現在の単結晶の実験からみて明らかに間違った結果を出している例も見られます.これも, 当時の技術力と言うよりは, 相転移のような微妙な構造変化の問題を取扱う時, リートベルト法は非常に注意が必要であると言う今日的な問題です.これら, 粉末回折でのリートベルト法の有利な点や適用範囲は何か, また, リートベルト自身がどのような問題点や注意点がこの方法にあると考えていたのかを原著論文で見ることは大変意義があると言えます.今回は, J. Appl. Cryst.に投稿されたリートベルト法の原点とも言える論文を易しく解説していただきます.

7 0 0 0 OA 学会ニュース

出版者
日本結晶学会
雑誌
日本結晶学会誌 (ISSN:03694585)
巻号頁・発行日
vol.56, no.3, pp.News3-News3, 2014-06-30 (Released:2014-07-09)