| 高分子 Vol.72 No.8 |
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特集 タンパク質を見る
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| 展望 COVER STORY: Highlight Reviews |
| タンパク質の相転移と溶液の相互溶解に基づく液－液相分離現象 Liquid-Liquid Phase Separation Based on Protein Phase Transition and Solution Mutual Solubility |
野本 晃・白木 賢太郎 Akira NOMOTO, Kentaro SHIRAKI |
| ＜要旨＞ タンパク質の液－液相分離現象は、細胞内の反応を調節する機構として注目されている。本稿では、液－液相分離するタンパク質の性質を整理したあと、タンパク質の本質的な相転移について熱力学の視点から解説する。最後に、液体の相互溶解といった溶液学の視点から、タンパク質の液－液相分離現象をどこまで理解できるか考察する。 Keywords: Liquid-Liquid Phase Separation / Protein / Amino Acid / Phase Transition / Melting Point / Mutual Solubility / Solubility Parameter / Protein Solution |
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| クライオ電子顕微鏡が観たカルシウムポンプの分子描像 Molecular Features of Calcium Pumps Revealed by Cryo-EM Analysis |
稲葉 謙次 Kenji INABA |
| ＜要旨＞ クライオ電子顕微鏡単粒子解析により、タンパク質の構造が比較的容易に決定できるのみならず、溶液中でタンパク質が本来もつ構造多型性やダイナミクスの情報さえも引き出すことが可能である。本稿では、本手法によって解明されたヒト由来小胞体カルシウムポンプSERCA2bとゴルジ体カルシウムポンプSPCA1aの構造とカルシウムイオン輸送機構について解説する。 Keywords: Cryo-EM / SERCA2b / SPCA1a / Ca2+ / Mn2+ / P-Type ATPase / ER / Golgi |
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| タンパク質標識技術によるイメージング法の進展 Recent Progress in Protein Labeling Techniques for Live-Cell Imaging |
上川 拓也・堀 雄一郎 Takuya KAMIKAWA, Yuichiro HORI |
| ＜要旨＞ タンパク質の局在や量的変化など多様な動態を明らかにすることは、その生理機能を明らかにするうえで重要な情報を提供する。合成蛍光プローブを用いたタンパク質標識技術は、強力な生細胞イメージングツールとして、広く用いられている。本稿では、近年のその技術開発の進展と展望、筆者らが独自に開発した標識技術について紹介する。 Keywords: Fluorescence Probe / Protein Tag / Halo Tag / PYP-Tag / OFF-ON-OFF Fluorescence Probe |
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| トピックス COVER STORY: Topics and Products |
| 常磁性金属を使ったタンパク質の構造変化解析 Conformational Study of Multi-Domain Proteins Using Paramagnetic Lanthanide Ions |
齋尾 智英 Tomohide SAIO |
| ＜要旨＞ Despite the functional importance of drastic conformational changes of multidomain proteins, the scarcity of efficient methods obscured mechanistic insights. Recent developments in the structural biology field exploiting paramagnetic lanthanide ions shed light on novel aspects of multidomain proteins in solution. Here I briefly introduce examples of structural studies on a multidomain protein by the use of paramagnetic lanthanide ions. Keywords: Solution Protein Structure / Paramagnetic Lanthanide Ions / Multi-Domain Protein / Conformational Change / Conformational Ensemble |
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| 高速原子間力顕微鏡（HS-AFM）によるチャネルタンパク質とリガンドの結合動態解析 Analysis of Binding Dynamics between Ion Channel and Ligand by High-Speed Atomic Force Microscopy |
角野 歩 Ayumi SUMINO |
| ＜要旨＞ Atomic force microscopy (AFM) can observe the surface structure of a sample by detecting the interaction force between the sample and the AFM probe. High-speed AFM (HS-AFM) is a fast scanning version of the AFM. Thanks to high spatiotemporal resolution of the HS-AFM (horizontal: 1nm, vertical: 0.1 nm, 0.1 sec/frame), the HS-AFM has been applied to single-molecule imaging of a wide variety of biomolecules including membrane proteins. This article describes a method to reconstitute ion channels suitable for HS-AFM observation and presents an example of applying this method to observe the binding dynamics of K+ channel KcsA and scorpion venom peptide AgTx2. The research examples presented here can be applied to other membrane proteins, and we expect to be able to elucidate the functional dynamics of various membrane proteins and membrane-bound molecules in the future. Keywords: High-Speed AFM / K+ Channel / Scorpion Toxin / Binding Kinetics / Induced Fit |
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| 中性子散乱によるタンパク質の動きの解析 Dynamics of Proteins in Solution as Seen by Neutron Scattering |
井上 倫太郎 Rintaro INOUE |
| ＜要旨＞ Various biomacromolecules including proteins exhibit various biological functions in the solution state. Hence, elucidation of both structure and dynamics of biomacromolecules in solution are indispensable for clarifying the functions. There are mainly two notable points associated with neutron scattering. One is a discernment of hydrogen from its isotope, deuterium due to the difference of their neutron scattering length. Since the energy of thermal fluctuation of biomacromolecules is comparable to that of a cold neutron, another point is a direct detection of dynamics of biomacromolecules. In this manuscript, I present two main topics focused on the detection and analysis of protein dynamics in solution. First is a detection of slow dynamics, subunit exchange of protein complex through the combination of small-angle neutron scattering and deuteration technique. Second is a detection of internal dynamics of proteins in solution through quasielastic neutron scattering. These studies reveal that neutron scattering is a quite fitting method for studying the dynamics of proteins in solution. Keywords: Neutron Scattering / Deuteration / Protein Complex / Internal Dynamics |
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| クライオ電子顕微鏡で生体高分子を観る Observing Macromolecular Assemblies by Cryo-Electron Microscopy |
横山 武司 Takeshi YOKOYAMA |
| ＜要旨＞ Cryo-electron microscopy (cryo-EM) is a powerful technique to directly observe macromolecular assemblies of proteins and nucleic acids embedded in amorphous ice using the transmission electron microscope. Recent advancement in this technique allows us to obtain high-resolution structures of macromolecules more efficiently than before. Single particle analysis (SPA) collects macromolecule images as particles and classifies them based on their structural differences. Therefore, comparing three-dimensional structures from the dataset facilitates us in understanding the dynamics of the molecule. Here, I present the overview of cryo-electron microscopy for analyzing macromolecular assemblies. Keywords: Cryo-Electron Microscopy / Macromolular Assembly / Ribosome |
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| グローイングポリマー Polymer Science and I: A Personal Account |
| ナノからポリ My Steps from NANO to POLY |
伊藤 麻絵 Asae ITO |
| ＜要旨＞ This article describes my journey to encounter polymers. Polymers brought an impact on me that it has a high-resistance to some contaminations, as I had been dealing with nanomaterials. I would be happy if I can tell the readers how polymers are wonderful materials and interesting research subjects. |
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| 高分子科学最近の進歩 Front-Line Polymer Science |
| π-スタック型環状オリゴマーと環状分子 π-Stacked Cyclic Oligomers and Macrocycles |
森崎 泰弘 Yasuhiro MORISAKI |
| ＜要旨＞ This short review focuses on optically active π-stacked oligomers and cyclic molecules based on planar chiral [2.2]paracyclophane scaffolds. [2.2]Paracyclophane is also a cyclic molecule consisting of face-to-face phenylenes stacked in proximity (approximately 3 Å between phenylenes). [2.2]Paracyclophanes with substituent(s) are planar chiral compounds without chiral centers because of the suppressed rotational motion of the stacked benzene rings. Recently, practical optical resolutions of [2.2]paracyclophanes by a diastereomer method have been reported, and enantiopure [2.2]paracyclophanes have been used as chiral building blocks for optically active π-stacked molecules. In addition, [2.2]paracyclophane-containing chiral cyclic oligomers have also been prepared from the corresponding racemate and separated by liquid chromatography using chiral columns. Many planar chiral [2.2]paracyclophanes consisting of chiral cyclic oligomers and macrocycles emit circulaly polarized luminescence (CPL) with good anisotropy factors. The structures of such chiral π-stacked cyclic oligomers and macrocycles and their excellent CPL profiles are introduced. Keywords: [2.2]Paracyclophane / Planar Chirality / Circularly Polarized Luminescence / Photoluminescence / π-Conjugation / π-Stacked Molecule / Macrocycle |
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