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Matsuki Y, Takashima M, Ueki M, Iwamoto M, Oiki S. Probing membrane deformation energy by KcsA potassium channel gating under varied membrane thickness and tension. FEBS Lett 2024; 598:1955-1966. [PMID: 38880762 DOI: 10.1002/1873-3468.14956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 06/18/2024]
Abstract
This study investigated how membrane thickness and tension modify the gating of KcsA potassium channels when simultaneously varied. The KcsA channel undergoes global conformational changes upon gating: expansion of the cross-sectional area and longitudinal shortening upon opening. Thus, membranes impose differential effects on the open and closed conformations, such as hydrophobic mismatches. Here, the single-channel open probability was recorded in the contact bubble bilayer, by which variable thickness membranes under a defined tension were applied. A fully open channel in thin membranes turned to sporadic openings in thick membranes, where the channel responded moderately to tension increase. Quantitative gating analysis prompted the hypothesis that tension augmented the membrane deformation energy when hydrophobic mismatch was enhanced in thick membranes.
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Affiliation(s)
- Yuka Matsuki
- Department of Anesthesiology and Reanimatology, Faculty of Medical Sciences, University of Fukui, Yoshida-gun, Japan
- Life Science Innovation Center, University of Fukui, Yoshida-gun, Japan
| | - Masako Takashima
- Department of Molecular Neuroscience, Faculty of Medical Sciences, University of Fukui, Yoshida-gun, Japan
| | - Misuzu Ueki
- Life Science Innovation Center, University of Fukui, Yoshida-gun, Japan
- Department of Molecular Neuroscience, Faculty of Medical Sciences, University of Fukui, Yoshida-gun, Japan
| | - Masayuki Iwamoto
- Life Science Innovation Center, University of Fukui, Yoshida-gun, Japan
- Department of Molecular Neuroscience, Faculty of Medical Sciences, University of Fukui, Yoshida-gun, Japan
| | - Shigetoshi Oiki
- Biomedical Imaging Research Center, University of Fukui, Yoshida-gun, Japan
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2
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Yang Y, Arai T, Sasaki D, Kuramochi M, Inagaki H, Ohashi S, Sekiguchi H, Mio K, Kubo T, Sasaki YC. Real-time tilting and twisting motions of ligand-bound states of α7 nicotinic acetylcholine receptor. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2024; 53:15-25. [PMID: 38233601 PMCID: PMC10853312 DOI: 10.1007/s00249-023-01693-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 11/29/2023] [Accepted: 12/01/2023] [Indexed: 01/19/2024]
Abstract
The α7 nicotinic acetylcholine receptor is a member of the nicotinic acetylcholine receptor family and is composed of five α7 subunits arranged symmetrically around a central pore. It is localized in the central nervous system and immune cells and could be a target for treating Alzheimer's disease and schizophrenia. Acetylcholine is a ligand that opens the channel, although prolonged application rapidly decreases the response. Ivermectin was reported as one of the positive allosteric modulators, since the binding of Ivermectin to the channel enhances acetylcholine-evoked α7 currents. One research has suggested that tilting motions of the nicotinic acetylcholine receptor are responsible for channel opening and activation. To verify this hypothesis applies to α7 nicotinic acetylcholine receptor, we utilized a diffracted X-ray tracking method to monitor the stable twisting and tilting motion of nAChR α7 without a ligand, with acetylcholine, with Ivermectin, and with both of them. The results show that the α7 nicotinic acetylcholine receptor twists counterclockwise with the channel transiently opening, transitioning to a desensitized state in the presence of acetylcholine and clockwise without the channel opening in the presence of Ivermectin. We propose that the conformational transition of ACh-bound nAChR α7 may be due to the collective twisting of the five α7 subunits, resulting in the compression and movement, either downward or upward, of one or more subunits, thus manifesting tilting motions. These tilting motions possibly represent the transition from the resting state to channel opening and potentially to the desensitized state.
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Affiliation(s)
- Yue Yang
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561, Japan
| | - Tatsuya Arai
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561, Japan
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa, 277-8565, Japan
| | - Daisuke Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561, Japan
| | - Masahiro Kuramochi
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561, Japan
- Graduate School of Science and Engineering, Ibaraki University, Hitachi, 316-8511, Japan
| | - Hidetoshi Inagaki
- Biomedical Research Insitute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan
| | - Sumiko Ohashi
- Biomedical Research Insitute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan
| | - Hiroshi Sekiguchi
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Kazuhiro Mio
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa, 277-8565, Japan
| | - Tai Kubo
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561, Japan
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa, 277-8565, Japan
| | - Yuji C Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8561, Japan.
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa, 277-8565, Japan.
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan.
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3
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Matsuki Y, Iwamoto M, Oiki S. Asymmetric Lipid Bilayers and Potassium Channels Embedded Therein in the Contact Bubble Bilayer. Methods Mol Biol 2024; 2796:1-21. [PMID: 38856892 DOI: 10.1007/978-1-0716-3818-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Cell membranes are highly intricate systems comprising numerous lipid species and membrane proteins, where channel proteins, lipid molecules, and lipid bilayers, as continuous elastic fabric, collectively engage in multi-modal interplays. Owing to the complexity of the native cell membrane, studying the elementary processes of channel-membrane interactions necessitates a bottom-up approach starting from forming simplified synthetic membranes. This is the rationale for establishing an in vitro membrane reconstitution system consisting of a lipid bilayer with a defined lipid composition and a channel molecule. Recent technological advancements have facilitated the development of asymmetric membranes, and the contact bubble bilayer (CBB) method allows single-channel current recordings under arbitrary lipid compositions in asymmetric bilayers. Here, we present an experimental protocol for the formation of asymmetric membranes using the CBB method. The KcsA potassium channel is a prototypical model channel with huge structural and functional information and thus serves as a reporter of membrane actions on the embedded channels. We demonstrate specific interactions of anionic lipids in the inner leaflet. Considering that the local lipid composition varies steadily in cell membranes, we `present a novel lipid perfusion technique that allows rapidly changing the lipid composition while monitoring the single-channel behavior. Finally, we demonstrate a leaflet perfusion method for modifying the composition of individual leaflets. These techniques with custom synthetic membranes allow for variable experiments, providing crucial insights into channel-membrane interplay in cell membranes.
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Affiliation(s)
- Yuka Matsuki
- Department of Anesthesiology and Reanimatology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Masayuki Iwamoto
- Department of Molecular Neuroscience, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Shigetoshi Oiki
- Biomedical Imaging Research Center, University of Fukui, Fukui, Japan.
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4
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Iwamoto M, Morito M, Oiki S, Nishitani Y, Yamamoto D, Matsumori N. Cardiolipin binding enhances KcsA channel gating via both its specific and dianion-monoanion interchangeable sites. iScience 2023; 26:108471. [PMID: 38077151 PMCID: PMC10709135 DOI: 10.1016/j.isci.2023.108471] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 10/29/2023] [Accepted: 11/13/2023] [Indexed: 01/17/2024] Open
Abstract
KcsA is a potassium channel with a plethora of structural and functional information, but its activity in the KcsA-producing actinomycete membranes remains elusive. To determine lipid species involved in channel-modulation, a surface plasmon resonance (SPR)-based methodology, characterized by immobilization of membrane proteins under a membrane environment, was applied. Dianionic cardiolipin (CL) showed extremely higher affinity for KcsA than monoanionic lipids. The SPR experiments further demonstrated that CL bound not only to the N-terminal M0 helix, a lipid-sensor domain, but to the M0 helix-deleted mutant. In contrast, monoanionic lipids interacted primarily with the M0 helix. This indicates the presence of an alternative CL-binding site, plausibly in the transmembrane domain. Single-channel recordings demonstrated that CL enhanced channel opening in an M0-independent manner. Taken together, the action of monoanionic lipids is exclusively mediated by the M0 helix, while CL binds both the M0 helix and its specific site, further enhancing the channel activity.
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Affiliation(s)
- Masayuki Iwamoto
- Department of Molecular Neuroscience, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Masayuki Morito
- Department of Chemistry, Graduate School of Science, Kyushu University, Fukuoka 819-0395 Japan
| | - Shigetoshi Oiki
- Biomedial Imaging Research Center, University of Fukui, Fukui 910-1193, Japan
| | - Yudai Nishitani
- Department of Applied Physics, Faculty of Science, Fukuoka University, Fukuoka 814-0180, Japan
| | - Daisuke Yamamoto
- Department of Applied Physics, Faculty of Science, Fukuoka University, Fukuoka 814-0180, Japan
| | - Nobuaki Matsumori
- Department of Chemistry, Graduate School of Science, Kyushu University, Fukuoka 819-0395 Japan
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Kuramochi M, Sugawara I, Shinkai Y, Mio K, Sasaki YC. Time-Resolved X-ray Observation of Intracellular Crystallized Protein in Living Animal. Int J Mol Sci 2023; 24:16914. [PMID: 38069236 PMCID: PMC10706802 DOI: 10.3390/ijms242316914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/26/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Understanding the cellular environment as molecular crowding that supports the structure-specific functional expression of biomolecules has recently attracted much attention. Time-resolved X-ray observations have the remarkable capability to capture the structural dynamics of biomolecules with subnanometre precision. Nevertheless, the measurement of the intracellular dynamics within live organisms remains a challenge. Here, we explore the potential of utilizing crystallized proteins that spontaneously form intracellular crystals to investigate their intracellular dynamics via time-resolved X-ray observations. We generated transgenic Caenorhabditis elegans specifically expressing the crystallized protein in cells and observed the formation of the protein aggregates within the animal cells. From the toxic-effect observations, the aggregates had minimal toxic effects on living animals. Fluorescence observations showed a significant suppression of the translational diffusion movements in molecules constituting the aggregates. Moreover, X-ray diffraction measurements provided diffraction signals originating from these molecules. We also observed the blinking behaviour of the diffraction spots, indicating the rotational motion of these crystals within the animal cells. A diffracted X-ray blinking (DXB) analysis estimated the rotational motion of the protein crystals on the subnanometre scale. Our results provide a time-resolved X-ray diffraction technique for the monitoring of intracellular dynamics.
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Affiliation(s)
- Masahiro Kuramochi
- Graduate School of Science and Engineering, Ibaraki University, Hitachi 316-8511, Japan;
| | - Ibuki Sugawara
- Graduate School of Science and Engineering, Ibaraki University, Hitachi 316-8511, Japan;
| | - Yoichi Shinkai
- Molecular Neurobiology Research Group, Biomedical Research Institute, National Institute of Advance Industrial Science and Technology (AIST), Tsukuba 305-8566, Japan;
| | - Kazuhiro Mio
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Kashiwa 277-8565, Japan;
| | - Yuji C. Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan;
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Sasaki YC. Diffracted X-ray Tracking for Observing the Internal Motions of Individual Protein Molecules and Its Extended Methodologies. Int J Mol Sci 2023; 24:14829. [PMID: 37834277 PMCID: PMC10573657 DOI: 10.3390/ijms241914829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
In 1998, the diffracted X-ray tracking (DXT) method pioneered the attainment of molecular dynamics measurements within individual molecules. This breakthrough revolutionized the field by enabling unprecedented insights into the complex workings of molecular systems. Similar to the single-molecule fluorescence labeling technique used in the visible range, DXT uses a labeling method and a pink beam to closely track the diffraction pattern emitted from the labeled gold nanocrystals. Moreover, by utilizing X-rays with extremely short wavelengths, DXT has achieved unparalleled accuracy and sensitivity, exceeding initial expectations. As a result, this remarkable advance has facilitated the search for internal dynamics within many protein molecules. DXT has recently achieved remarkable success in elucidating the internal dynamics of membrane proteins in living cell membranes. This breakthrough has not only expanded our knowledge of these important biomolecules but also has immense potential to advance our understanding of cellular processes in their native environment.
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Affiliation(s)
- Yuji C. Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan;
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho 679-5198, Japan
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Oda M. Analysis of the Structural Dynamics of Proteins in the Ligand-Unbound and -Bound States by Diffracted X-ray Tracking. Int J Mol Sci 2023; 24:13717. [PMID: 37762021 PMCID: PMC10531450 DOI: 10.3390/ijms241813717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/03/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Although many protein structures have been determined at atomic resolution, the majority of them are static and represent only the most stable or averaged structures in solution. When a protein binds to its ligand, it usually undergoes fluctuation and changes its conformation. One attractive method for obtaining an accurate view of proteins in solution, which is required for applications such as the rational design of proteins and structure-based drug design, is diffracted X-ray tracking (DXT). DXT can detect the protein structural dynamics on a timeline via gold nanocrystals attached to the protein. Here, the structure dynamics of single-chain Fv antibodies, helix bundle-forming de novo designed proteins, and DNA-binding proteins in both ligand-unbound and ligand-bound states were analyzed using the DXT method. The resultant mean square angular displacements (MSD) curves in both the tilting and twisting directions clearly demonstrated that structural fluctuations were suppressed upon ligand binding, and the binding energies determined using the angular diffusion coefficients from the MSD agreed well with the binding thermodynamics determined using isothermal titration calorimetry. In addition, the size of gold nanocrystals is discussed, which is one of the technical concerns of DXT.
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Affiliation(s)
- Masayuki Oda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan
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8
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Mio K, Ohkubo T, Sasaki D, Arai T, Sugiura M, Fujimura S, Nozawa S, Sekiguchi H, Kuramochi M, Sasaki YC. Real-Time Observation of Capsaicin-Induced Intracellular Domain Dynamics of TRPV1 Using the Diffracted X-ray Tracking Method. MEMBRANES 2023; 13:708. [PMID: 37623769 PMCID: PMC10456751 DOI: 10.3390/membranes13080708] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 08/26/2023]
Abstract
The transient receptor potential vanilloid type 1 (TRPV1) is a multimodal receptor which responds to various stimuli, including capsaicin, protons, and heat. Recent advances in cryo-electron microscopy have revealed the structures of TRPV1. However, due to the large size of TRPV1 and its structural complexity, the detailed process of channel gating has not been well documented. In this study, we applied the diffracted X-ray tracking (DXT) technique to analyze the intracellular domain dynamics of the TRPV1 protein. DXT enables the capture of intramolecular motion through the analysis of trajectories of Laue spots generated from attached gold nanocrystals. Diffraction data were recorded at two different frame rates: 100 μs/frame and 12.5 ms/frame. The data from the 100 μs/frame recording were further divided into two groups based on the moving speed, using the lifetime filtering technique, and they were analyzed separately. Capsaicin increased the slope angle of the MSD curve of the C-terminus in 100 μs/frame recording, which accompanied a shifting of the rotational bias toward the counterclockwise direction, as viewed from the cytoplasmic side. This capsaicin-induced fluctuation was not observed in the 12.5 ms/frame recording, indicating that it is a high-frequency fluctuation. An intrinsiccounterclockwise twisting motion was observed in various speed components at the N-terminus, regardless of the capsaicin administration. Additionally, the competitive inhibitor AMG9810 induced a clockwise twisting motion, which is the opposite direction to capsaicin. These findings contribute to our understanding of the activation mechanisms of the TRPV1 channel.
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Affiliation(s)
- Kazuhiro Mio
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Tatsunari Ohkubo
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Daisuke Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan (T.A.)
| | - Tatsuya Arai
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan (T.A.)
| | - Mayui Sugiura
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
| | - Shoko Fujimura
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
| | - Shunsuke Nozawa
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba 305-0801, Japan;
| | - Hiroshi Sekiguchi
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho 679-5198, Japan
| | - Masahiro Kuramochi
- Graduate School of Science and Engineering, Ibaraki University, Hitachi 316-8511, Japan
| | - Yuji C. Sasaki
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan (T.A.)
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho 679-5198, Japan
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9
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Ohkubo T, Shiina T, Kawaguchi K, Sasaki D, Inamasu R, Yang Y, Li Z, Taninaka K, Sakaguchi M, Fujimura S, Sekiguchi H, Kuramochi M, Arai T, Tsuda S, Sasaki YC, Mio K. Visualizing Intramolecular Dynamics of Membrane Proteins. Int J Mol Sci 2022; 23:ijms232314539. [PMID: 36498865 PMCID: PMC9736139 DOI: 10.3390/ijms232314539] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/18/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022] Open
Abstract
Membrane proteins play important roles in biological functions, with accompanying allosteric structure changes. Understanding intramolecular dynamics helps elucidate catalytic mechanisms and develop new drugs. In contrast to the various technologies for structural analysis, methods for analyzing intramolecular dynamics are limited. Single-molecule measurements using optical microscopy have been widely used for kinetic analysis. Recently, improvements in detectors and image analysis technology have made it possible to use single-molecule determination methods using X-rays and electron beams, such as diffracted X-ray tracking (DXT), X-ray free electron laser (XFEL) imaging, and cryo-electron microscopy (cryo-EM). High-speed atomic force microscopy (HS-AFM) is a scanning probe microscope that can capture the structural dynamics of biomolecules in real time at the single-molecule level. Time-resolved techniques also facilitate an understanding of real-time intramolecular processes during chemical reactions. In this review, recent advances in membrane protein dynamics visualization techniques were presented.
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Affiliation(s)
- Tatsunari Ohkubo
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Takaaki Shiina
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
| | - Kayoko Kawaguchi
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
| | - Daisuke Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Rena Inamasu
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Yue Yang
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Zhuoqi Li
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Keizaburo Taninaka
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Masaki Sakaguchi
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Shoko Fujimura
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Hiroshi Sekiguchi
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5198, Japan
| | - Masahiro Kuramochi
- Graduate School of Science and Engineering, Ibaraki University, Hitachi 316-8511, Japan
| | - Tatsuya Arai
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Sakae Tsuda
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Yuji C. Sasaki
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5198, Japan
| | - Kazuhiro Mio
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
- Correspondence:
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10
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Diffracted X-ray Tracking Method for Measuring Intramolecular Dynamics of Membrane Proteins. Int J Mol Sci 2022; 23:ijms23042343. [PMID: 35216461 PMCID: PMC8880040 DOI: 10.3390/ijms23042343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 02/14/2022] [Accepted: 02/17/2022] [Indexed: 02/06/2023] Open
Abstract
Membrane proteins change their conformations in response to chemical and physical stimuli and transmit extracellular signals inside cells. Several approaches have been developed for solving the structures of proteins. However, few techniques can monitor real-time protein dynamics. The diffracted X-ray tracking method (DXT) is an X-ray-based single-molecule technique that monitors the internal motion of biomolecules in an aqueous solution. DXT analyzes trajectories of Laue spots generated from the attached gold nanocrystals with a two-dimensional axis by tilting (θ) and twisting (χ). Furthermore, high-intensity X-rays from synchrotron radiation facilities enable measurements with microsecond-timescale and picometer-spatial-scale intramolecular information. The technique has been applied to various membrane proteins due to its superior spatiotemporal resolution. In this review, we introduce basic principles of DXT, reviewing its recent and extended applications to membrane proteins and living cells, respectively.
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11
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Iwamoto M, Oiki S. Hysteresis of a Tension-Sensitive K + Channel Revealed by Time-Lapse Tension Measurements. JACS AU 2021; 1:467-474. [PMID: 34467309 PMCID: PMC8395652 DOI: 10.1021/jacsau.0c00098] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Indexed: 05/05/2023]
Abstract
Various types of channels vary their function by membrane tension changes upon cellular activities, and lipid bilayer methods allow elucidation of direct interaction between channels and the lipid bilayer. However, the dynamic responsiveness of the channel to the membrane tension remains elusive. Here, we established a time-lapse tension measurement system. A bilayer is formed by docking two monolayer-lined water bubbles, and tension is evaluated via measuring intrabubble pressure as low as <100 Pa (Young-Laplace principle). The prototypical KcsA potassium channel is tension-sensitive, and single-channel current recordings showed that the activation gate exhibited distinct tension sensitivity upon stretching and relaxing. The mechanism underlying the hysteresis is discussed in the mode shift regime, in which the channel protein bears short "memory" in their conformational changes.
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Affiliation(s)
- Masayuki Iwamoto
- Department
of Molecular Neuroscience, University of
Fukui Faculty of Medical Science, 910-1193 Fukui, Japan
| | - Shigetoshi Oiki
- Biomedical
Imaging Research Center, University of Fukui, 910-1193 Fukui, Japan
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12
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Chang J, Baek Y, Lee I, Sekiguchi H, Ichiyanagi K, Mio K, Nozawa S, Fukaya R, Adachi SI, Kuramochi M, Sasaki YC. Diffracted X-ray blinking measurements of interleukin 15 receptors in the inner/outer membrane of living NK cells. Biochem Biophys Res Commun 2021; 556:53-58. [PMID: 33839414 DOI: 10.1016/j.bbrc.2021.03.144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 03/25/2021] [Indexed: 02/06/2023]
Abstract
Interleukin 15 receptor (IL-15R) is a transmembrane signalling protein consisting of 3 subsets: α, β (IL-15Rβ), and γ (γc). IL-2 and IL-15 share the signalling domains IL-15Rβ and γc, although they bind to intrinsic α-subsets and non-signalling domains. Additionally, IL-2 and IL-15 play different roles; therefore, there have been many observations of the dynamic behaviours of IL-15R, which are linked to physiological functions. For more practical discrimination between IL-2 and IL-15, a study was designed and carried out in which α-subsets were removed and a cytoplasmic inhibitor was applied to create a simplified environment in which secondary signalling molecules were reduced. We also applied a new measurement method, diffracted X-ray blinking (DXB), to achieve higher accuracy (<0.01 Å). The dynamics of IL-2 binding (confined motion, max range = 0.71 Å) and IL-15 binding (normal motion) in live natural killer cells were different. We also confirmed. that DXB was a suitable method to quantitatively evaluate the transmembrane protein dynamics of inner/outer live cell membranes by labeling the extracellular domain since the measurements were dependent on the cytosolic environment.
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Affiliation(s)
- Jaewon Chang
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan
| | - Yonugseok Baek
- Department of Biomedical Science, CHA University, 335, Pangyo-ro, Bundang, Seongnam, 13488, Gyeonggi, Republic of Korea; Immunotherapy Team, NBE, R&D Division, CHA BIOTECH, 335, Pangyo-ro, Bundang, Seongnam, 13488, Gyeonggi, Republic of Korea
| | - Injee Lee
- Department of Biomedical Science, CHA University, 335, Pangyo-ro, Bundang, Seongnam, 13488, Gyeonggi, Republic of Korea; Immunotherapy Team, NBE, R&D Division, CHA BIOTECH, 335, Pangyo-ro, Bundang, Seongnam, 13488, Gyeonggi, Republic of Korea
| | - Hiroshi Sekiguchi
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, 679-5198, Hyogo, Japan
| | - Kouhei Ichiyanagi
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, 305-0801, Ibaraki, Japan; Division of Biophysics, Department of Physiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, 329-0498, Tochigi, Japan
| | - Kazuhiro Mio
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-3-26 Aomi, 135-0064, Tokyo, Japan; AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan
| | - Shunsuke Nozawa
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, 305-0801, Ibaraki, Japan
| | - Ryo Fukaya
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, 305-0801, Ibaraki, Japan
| | - Shin-Ichi Adachi
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, 305-0801, Ibaraki, Japan
| | - Masahiro Kuramochi
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan; AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan.
| | - Yuji C Sasaki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan; Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, 679-5198, Hyogo, Japan; AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Kashiwa, 277-8561, Chiba, Japan.
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13
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Fujimura S, Mio K, Kuramochi M, Sekiguchi H, Ikezaki K, Mio M, Hengphasatporn K, Shigeta Y, Kubo T, Sasaki YC. Agonist and Antagonist-Diverted Twisting Motions of a Single TRPV1 Channel. J Phys Chem B 2020; 124:11617-11624. [PMID: 33296594 DOI: 10.1021/acs.jpcb.0c08250] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Transient receptor potential vanilloid type 1 (TRPV1) channels are activated by heat, vanilloids, and extracellular protons. Cryo-EM has revealed various conformations of TRPV1, and these structures suggest an intramolecular twisting motion in response to ligand binding. However, limited experimental data support this observation. Here, we analyzed the intramolecular motion of TRPV1 using diffracted X-ray tracking (DXT). DXT analyzes trajectories of Laue spots generated from attached gold nanocrystals and provides picometer spatial and microsecond time scale information about the intramolecular motion. We observed that both an agonist and a competitive antagonist evoked a rotating bias in TRPV1, though these biases were in opposing directions. Furthermore, the rotational bias generated by capsaicin was reversed between the wild-type and the capsaicin-insensitive Y511A mutant. Our findings bolster the understanding of the mechanisms used for activation and modulation of TRP channels, and this knowledge can be exploited for pharmacological usage such as inhibitor design.
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Affiliation(s)
- Shoko Fujimura
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan
| | - Kazuhiro Mio
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan.,Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Chiba 277-0882, Japan
| | - Masahiro Kuramochi
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan.,Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Hiroshi Sekiguchi
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Hyogo 567-5198, Japan
| | - Keigo Ikezaki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan
| | - Muneyo Mio
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan.,Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-3-26 Aomi, Tokyo 135-0064, Japan
| | - Kowit Hengphasatporn
- Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Yasuteru Shigeta
- Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Tai Kubo
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan.,Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-3-26 Aomi, Tokyo 135-0064, Japan
| | - Yuji C Sasaki
- AIST-UTokyo Advanced Operando-Measurement Technology Open Innovation Laboratory (OPERANDO-OIL), National Institute of Advanced Industrial Science and Technology (AIST), 6-2-3 Kashiwanoha, Chiba 277-0882, Japan.,Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Chiba 277-8561, Japan.,Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Hyogo 567-5198, Japan
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14
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Shibayama N. Allosteric transitions in hemoglobin revisited. Biochim Biophys Acta Gen Subj 2020; 1864:129335. [DOI: 10.1016/j.bbagen.2019.03.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 03/27/2019] [Accepted: 03/30/2019] [Indexed: 12/19/2022]
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15
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Xu Y, McDermott AE. Inactivation in the potassium channel KcsA. JOURNAL OF STRUCTURAL BIOLOGY-X 2019; 3:100009. [PMID: 32647814 PMCID: PMC7337057 DOI: 10.1016/j.yjsbx.2019.100009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 05/17/2019] [Accepted: 06/04/2019] [Indexed: 12/17/2022]
Abstract
C-type inactivation in potassium channels is a nearly universal regulatory mechanism. A major hypothesis states that C-type inactivation involves ion loss at the selectivity filter as an allosteric response to activation. NMR is used to probe protein conformational changes in response to pH and [K+], demonstrating that H+ and K+ binding are allosterically coupled in KcsA. The lipids are integrated parts of potassium channels in terms of structure, energetics and function.
Inactivation, the slow cessation of transmission after activation, is a general feature of potassium channels. It is essential for their function, and malfunctions in inactivation leads to numerous pathologies. The detailed mechanism for the C-type inactivation, distinct from the N-type inactivation, remains an active area of investigation. Crystallography, computational simulations, and NMR have greatly enriched our understanding of the process. Here we review the major hypotheses regarding C-type inactivation, particularly focusing on the key role played by NMR studies of the prokaryotic potassium channel KcsA, which serves as a good model for voltage gated mammalian channels.
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Affiliation(s)
- Yunyao Xu
- Department of Chemistry, Columbia University, New York, NY 10027, United States
| | - Ann E McDermott
- Department of Chemistry, Columbia University, New York, NY 10027, United States
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16
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Diffracted X-ray tracking method for recording single-molecule protein motions. Biochim Biophys Acta Gen Subj 2019; 1864:129361. [PMID: 31077793 DOI: 10.1016/j.bbagen.2019.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 04/25/2019] [Accepted: 05/05/2019] [Indexed: 11/24/2022]
Abstract
BACKGROUND Proteins change their conformation depending on function. Although a vast number of static pictures of proteins have been accumulated, information regarding their dynamics in function is limited. Diffracted X-ray tracking (DXT) is a good candidate to obtain the missing data. SCOPE OF REVIEW A gold nanocrystal was attached to the target protein as a probe and the motion of the X-ray diffraction spots from the crystal corresponded to the motion of the target. Although it has advantages of high temporal (sub-millisecond) and spatial (approximately 0.1°) resolutions, it is not extensively utilized. This review focused on its effective application from a user's perspective. We also present an example with the KcsA channel and the status of recent developments to show the future possibilities of the method. MAJOR CONCLUSIONS DXT is a powerful method to investigate intramolecular structural changes. For instance, in the KcsA channel, the method revealed a wave of conformational changes transmitted from the gate region to the end of the molecule. The method is continuously being developed, and users can choose an appropriate measurement system depending on the condition of their sample. GENERAL SIGNIFICANCE Revealing the protein structural changes with respect to function is an important frontier. The most distinctive feature of the DXT method is that both high temporal and spatial resolutions are achievable, and it is possible to track the motions of multiple molecules at the same time. This feature is an advantage for screening molecules associated with the target proteins (e.g., ligands and medicines).
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17
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Constitutive boost of a K + channel via inherent bilayer tension and a unique tension-dependent modality. Proc Natl Acad Sci U S A 2018; 115:13117-13122. [PMID: 30509986 DOI: 10.1073/pnas.1812282115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Molecular mechanisms underlying channel-membrane interplay have been extensively studied. Cholesterol, as a major component of the cell membrane, participates either in specific binding to channels or via modification of membrane physical features. Here, we examined the action of various sterols (cholesterol, epicholesterol, etc.) on a prototypical potassium channel (KcsA). Single-channel current recordings of the KcsA channel were performed in a water-in-oil droplet bilayer (contact bubble bilayer) with a mixed phospholipid composition (azolectin). Upon membrane perfusion of sterols, the activated gate at acidic pH closed immediately, irrespective of the sterol species. During perfusion, we found that the contacting bubbles changed their shapes, indicating alterations in membrane physical features. Absolute bilayer tension was measured according to the principle of surface chemistry, and inherent bilayer tension was ∼5 mN/m. All tested sterols decreased the tension, and the nonspecific sterol action to the channel was likely mediated by the bilayer tension. Purely mechanical manipulation that reduced bilayer tension also closed the gate, whereas the resting channel at neutral pH never activated upon increased tension. Thus, rather than conventional stretch activation, the channel, once ready to activate by acidic pH, changes the open probability through the action of bilayer tension. This constitutes a channel regulating modality by two successive stimuli. In the contact bubble bilayer, inherent bilayer tension was high, and the channel remained boosted. In the cell membrane, resting tension is low, and it is anticipated that the ready-to-activate channel remains closed until bilayer tension reaches a few millinewton/meter during physiological and pathological cellular activities.
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18
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Sekiguchi H, Kuramochi M, Ikezaki K, Okamura Y, Yoshimura K, Matsubara K, Chang JW, Ohta N, Kubo T, Mio K, Suzuki Y, Chavas LMG, Sasaki YC. Diffracted X-ray Blinking Tracks Single Protein Motions. Sci Rep 2018; 8:17090. [PMID: 30504916 PMCID: PMC6269541 DOI: 10.1038/s41598-018-35468-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 11/06/2018] [Indexed: 11/09/2022] Open
Abstract
Single molecule dynamics studies have begun to use quantum probes. Single particle analysis using cryo-transmission electron microscopy has dramatically improved the resolution when studying protein structures and is shifting towards molecular motion observations. X-ray free-electron lasers are also being explored as routes for determining single molecule structures of biological entities. Here, we propose a new X-ray single molecule technology that allows observation of molecular internal motion over long time scales, ranging from milliseconds up to 103 seconds. Our method uses both low-dose monochromatic X-rays and nanocrystal labelling technology. During monochromatic X-ray diffraction experiments, the intensity of X-ray diffraction from moving single nanocrystals appears to blink because of Brownian motion in aqueous solutions. X-ray diffraction spots from moving nanocrystals were observed to cycle in and out of the Bragg condition. Consequently, the internal motions of a protein molecule labelled with nanocrystals could be extracted from the time trajectory using this diffracted X-ray blinking (DXB) approach. Finally, we succeeded in distinguishing the degree of fluctuation motions of an individual acetylcholine-binding protein (AChBP) interacting with acetylcholine (ACh) using a laboratory X-ray source.
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Affiliation(s)
- Hiroshi Sekiguchi
- Research & Utilization Div., Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo, 567-5198, Japan.
| | - Masahiro Kuramochi
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Keigo Ikezaki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Yu Okamura
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Kazuki Yoshimura
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Ken Matsubara
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Jae-Won Chang
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Noboru Ohta
- Research & Utilization Div., Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo, 567-5198, Japan
| | - Tai Kubo
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan.,JapanAIST-UTokyo Advanced Operando Measurement Technology Open Innovation Laboratory, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Kazuhiro Mio
- Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan.,JapanAIST-UTokyo Advanced Operando Measurement Technology Open Innovation Laboratory, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Yoshio Suzuki
- Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan
| | - Leonard M G Chavas
- Proxima-I, Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin, BP 48 91192, Gif-sur-Yvette Cedex, France
| | - Yuji C Sasaki
- Research & Utilization Div., Japan Synchrotron Radiation Research Institute, 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo, 567-5198, Japan. .,Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan. .,JapanAIST-UTokyo Advanced Operando Measurement Technology Open Innovation Laboratory, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan.
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19
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Oiki S, Iwamoto M. Lipid Bilayers Manipulated through Monolayer Technologies for Studies of Channel-Membrane Interplay. Biol Pharm Bull 2018; 41:303-311. [PMID: 29491206 DOI: 10.1248/bpb.b17-00708] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fluidity and mosaicity are two critical features of biomembranes, by which membrane proteins function through chemical and physical interactions within a bilayer. To understand this complex and dynamic system, artificial lipid bilayer membranes have served as unprecedented tools for experimental examination, in which some aspects of biomembrane features have been extracted, and to which various methodologies have been applied. Among the lipid bilayers involving liposomes, planar lipid bilayers and nanodiscs, recent developments of lipid bilayer methods and the results of our channel studies are reviewed herein. Principles and techniques of bilayer formation are summarized, which have been extended to the current techniques, where a bilayer is formed from lipid-coated water-in-oil droplets (water-in-oil bilayer). In our newly developed method, termed the contact bubble bilayer (CBB) method, a water bubble is blown from a pipette into a bulk oil phase, and monolayer-lined bubbles are docked to form a bilayer through manipulation by pipette. An asymmetric bilayer can be readily formed, and changes in composition in one leaflet were possible. Taking advantage of the topological configuration of the CBB, such that the membrane's hydrophobic interior is contiguous with the surrounding bulk organic phase, oil-dissolved substances such as cholesterol were delivered directly to the bilayer interior to perfuse around the membrane-embedded channels (membrane perfusion), and current recordings in the single-channel allowed detection of immediate changes in the channels' response to cholesterol. Chemical and mechanical manipulation in each monolayer (monolayer technology) allows the examination of dynamic channel-membrane interplay.
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Affiliation(s)
- Shigetoshi Oiki
- Department of Molecular Physiology & Biophysics, University of Fukui Faculty of Medical Sciences
| | - Masayuki Iwamoto
- Department of Molecular Physiology & Biophysics, University of Fukui Faculty of Medical Sciences
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20
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X-ray observations of single bio-supramolecular photochirogenesis. Biophys Chem 2018; 242:1-5. [PMID: 30153504 DOI: 10.1016/j.bpc.2018.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/06/2018] [Accepted: 07/07/2018] [Indexed: 12/22/2022]
Abstract
The binding and photochirogenic behaviour of 2-anthracenecarboxylate (AC) with human serum albumin (HSA) have hitherto been investigated and comprehended as time-averaged statistical events by spectroscopic examinations and product analyses. In this study, we employed a diffracted X-ray tracking (DXT) technique to visualize the single-molecular dynamics of free and AC-loaded HSA (AC:HSA = 0, 1, 5 and 10), as well as the AC-HSA complex under photoirradiation, all of which were tethered to gold nanocrystals and hence traceable in real time by DXT. This enabled us to draw a more dynamic picture of the bio-supramolecular photochirogenesis at a single-molecule resolution, detailing the softening and flexibility enhancement of HSA upon binding of ACs to its inter-subdomain IIA-IIB site and the dynamic extrusion of AC dimers produced upon photoirradiation.
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21
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Time-Resolved Measurement of the ATP-Dependent Motion of the Group II Chaperonin by Diffracted Electron Tracking. Int J Mol Sci 2018; 19:ijms19040950. [PMID: 29565826 PMCID: PMC5979372 DOI: 10.3390/ijms19040950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 03/18/2018] [Accepted: 03/19/2018] [Indexed: 11/24/2022] Open
Abstract
Previously, we demonstrated the ATP-dependent dynamics of a group II chaperonin at the single-molecule level by diffracted X-ray tracking (DXT). The disadvantage of DXT is that it requires a strong X-ray source and also perfect gold nano-crystals. To resolve this problem, we developed diffracted electron tracking (DET). Electron beams have scattering cross-sections that are approximately 1000 times larger than those of X-rays. Thus, DET enables us to perform super-accurate measurements of the time-resolved 3D motion of proteins labeled with commercially available gold nanorods using a scanning electron microscope. In this study, we compared DXT and DET using the group II chaperonin from Methanococcus maripaludis (MmCpn) as a model protein. In DET, the samples are prepared in an environmental cell (EC). To reduce the electron beam-induced protein damage, we immobilized MmCpn on the bottom of the EC to expose gold nanorods close to the carbon thin film. The sample setup worked well, and the motions of gold nanorods were clearly traced. Compared with the results of DXT, the mobility in DET was significantly higher, which is probably due to the difference in the method for immobilization. In DET, MmCpn was immobilized on a film of triacetyl cellulose. Whereas proteins are directly attached on the surface of solid support in DXT. Therefore, MmCpn could move relatively freely in DET. DET will be a state-of-the-art technology for analyzing protein dynamics.
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22
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Abstract
Transmembrane protein 16F (TMEM16F) is a Ca2+-dependent phospholipid scramblase that translocates phospholipids bidirectionally between the leaflets of the plasma membrane. Phospholipid scrambling of TMEM16F causes exposure of phosphatidylserine in activated platelets to induce blood clotting and in differentiated osteoblasts to promote bone mineralization. Despite the importance of TMEM16F-mediated phospholipid scrambling in various biological reactions, the fundamental features of the scrambling reaction remain elusive due to technical difficulties in the preparation of a platform for assaying scramblase activity in vitro. Here, we established a method to express and purify mouse TMEM16F as a dimeric molecule by constructing a stable cell line and developed a microarray containing membrane bilayers with asymmetrically distributed phospholipids as a platform for single-molecule scramblase assays. The purified TMEM16F was integrated into the microarray, and monitoring of phospholipid translocation showed that a single TMEM16F molecule transported phospholipids nonspecifically between the membrane bilayers in a Ca2+-dependent manner. Thermodynamic analysis of the reaction indicated that TMEM16F transported 4.5 × 104 lipids per second at 25 °C, with an activation free energy of 47 kJ/mol. These biophysical features were similar to those observed with channels, which transport substrates by facilitating diffusion, and supported the stepping-stone model for the TMEM16F phospholipid scramblase.
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23
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Usui D, Inaba S, Sekiguchi H, Sasaki YC, Tanaka T, Oda M. First observation of metal ion-induced structural fluctuations of α-helical peptides by using diffracted X-ray tracking. Biophys Chem 2017; 228:81-86. [DOI: 10.1016/j.bpc.2017.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 07/12/2017] [Accepted: 07/12/2017] [Indexed: 10/19/2022]
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24
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Mowrey DD, Xu L, Mei Y, Pasek DA, Meissner G, Dokholyan NV. Ion-pulling simulations provide insights into the mechanisms of channel opening of the skeletal muscle ryanodine receptor. J Biol Chem 2017; 292:12947-12958. [PMID: 28584051 DOI: 10.1074/jbc.m116.760199] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/20/2017] [Indexed: 12/13/2022] Open
Abstract
The type 1 ryanodine receptor (RyR1) mediates Ca2+ release from the sarcoplasmic reticulum to initiate skeletal muscle contraction and is associated with muscle diseases, malignant hyperthermia, and central core disease. To better understand RyR1 channel function, we investigated the molecular mechanisms of channel gating and ion permeation. An adequate model of channel gating requires accurate, high-resolution models of both open and closed states of the channel. To this end, we generated an open-channel RyR1 model using molecular simulations to pull Ca2+ through the pore constriction site of a closed-channel RyR1 structure determined at 3.8-Å resolution. Importantly, we find that our open-channel model is consistent with the RyR1 and cardiac RyR (RyR2) open-channel structures reported while this paper was in preparation. Both our model and the published structures show similar rotation of the upper portion of the pore-lining S6 helix away from the 4-fold channel axis and twisting of Ile-4937 at the channel constriction site out of the channel pore. These motions result in a minimum open-channel pore radius of ∼3 Å formed by Gln-4933, rather than Ile-4937 in the closed-channel structure. We also present functional support for our model by mutations around the closed- and open-channel constriction sites (Gln-4933 and Ile-4937). Our results indicate that use of ion-pulling simulations produces a RyR1 open-channel model, which can provide insights into the mechanisms of channel opening complementing those from the structural data.
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Affiliation(s)
- David D Mowrey
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7260
| | - Le Xu
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7260
| | - Yingwu Mei
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7260
| | - Daniel A Pasek
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7260
| | - Gerhard Meissner
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7260.
| | - Nikolay V Dokholyan
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7260.
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25
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Sumino A, Uchihashi T, Oiki S. Oriented Reconstitution of the Full-Length KcsA Potassium Channel in a Lipid Bilayer for AFM Imaging. J Phys Chem Lett 2017; 8:785-793. [PMID: 28139934 DOI: 10.1021/acs.jpclett.6b03058] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Here, we have developed a method of oriented reconstitution of the KcsA potassium channel amenable to high-resolution AFM imaging. The solubilized full-length KcsA channels with histidine-tagged (His-tag) C-terminal ends were attached to a Ni2+-coated mica surface, and then detergent-destabilized liposomes were added to fill the interchannel space. AFM revealed that the membrane-embedded KcsA channels were oriented with their extracellular faces upward, seen as a tetrameric square shape. This orientation was corroborated by the visible binding of a peptide scorpion toxin, agitoxin-2. To observe the cytoplasmic side of the channel, a His-tag was inserted into the extracellular loop, and the oppositely oriented channels provided wholly different images. In either orientation, the channels were individually dispersed at acidic pH, whereas they were self-assembled at neutral pH, indicating that the oriented channels are allowed to diffuse in the membrane. This method is readily applicable to membrane proteins in general for AFM imaging.
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Affiliation(s)
- Ayumi Sumino
- PRESTO, Japan Science and Technology Agency (JST) , 4-1-8 Honcho, Kawaguchi-shi, Saitama 332-0012, Japan
- Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui , 23-3 Matsuokashimoaizuki, Yoshida-gun, Fukui 910-1193, Japan
| | - Takayuki Uchihashi
- Department of Physics, Kanazawa University , Kakuma-machi, Kanazawa 920-1192, Japan
- Bio-AFM Frontier Research Center , Kanazawa 920-1192, Japan
| | - Shigetoshi Oiki
- Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui , 23-3 Matsuokashimoaizuki, Yoshida-gun, Fukui 910-1193, Japan
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26
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Sato Y, Tanaka Y, Inaba S, Sekiguchi H, Maruno T, Sasaki YC, Fukada H, Kobayashi Y, Azuma T, Oda M. Structural dynamics of a single-chain Fv antibody against (4-hydroxy-3-nitrophenyl)acetyl. Int J Biol Macromol 2016; 91:151-7. [DOI: 10.1016/j.ijbiomac.2016.05.074] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/18/2016] [Accepted: 05/20/2016] [Indexed: 10/21/2022]
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27
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Sumikama T, Oiki S. Digitalized K+ Occupancy in the Nanocavity Holds and Releases Queues of K+ in a Channel. J Am Chem Soc 2016; 138:10284-92. [DOI: 10.1021/jacs.6b05270] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Takashi Sumikama
- Department of Molecular Physiology
and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
| | - Shigetoshi Oiki
- Department of Molecular Physiology
and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan
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28
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Khantwal CM, Abraham SJ, Han W, Jiang T, Chavan TS, Cheng RC, Elvington SM, Liu CW, Mathews II, Stein RA, Mchaourab HS, Tajkhorshid E, Maduke M. Revealing an outward-facing open conformational state in a CLC Cl(-)/H(+) exchange transporter. eLife 2016; 5. [PMID: 26799336 PMCID: PMC4769167 DOI: 10.7554/elife.11189] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 01/14/2016] [Indexed: 11/22/2022] Open
Abstract
CLC secondary active transporters exchange Cl- for H+. Crystal structures have suggested that the conformational change from occluded to outward-facing states is unusually simple, involving only the rotation of a conserved glutamate (Gluex) upon its protonation. Using 19F NMR, we show that as [H+] is increased to protonate Gluex and enrich the outward-facing state, a residue ~20 Å away from Gluex, near the subunit interface, moves from buried to solvent-exposed. Consistent with functional relevance of this motion, constriction via inter-subunit cross-linking reduces transport. Molecular dynamics simulations indicate that the cross-link dampens extracellular gate-opening motions. In support of this model, mutations that decrease steric contact between Helix N (part of the extracellular gate) and Helix P (at the subunit interface) remove the inhibitory effect of the cross-link. Together, these results demonstrate the formation of a previously uncharacterized 'outward-facing open' state, and highlight the relevance of global structural changes in CLC function. DOI:http://dx.doi.org/10.7554/eLife.11189.001 Cells have transporter proteins on their surface to carry molecules in and out of the cell. For example, the CLC family of transporters move two chloride ions in one direction at the same time as moving one hydrogen ion in the opposite direction. To be able to move these ions in opposite directions, transporters have to cycle through a series of shapes in which the ions can only access alternate sides of the membrane. First, the transporter adopts an 'outward-facing' shape when the ions first bind to the transporter, then it switches into the 'occluded' shape to move the ions through the membrane. Finally, the transporter takes on the 'inward-facing' shape to release the ions on the other side of the membrane. However, structural studies of CLCs suggest that the structures of these proteins do not change much while they are moving ions, which suggests that they might work in a different way. Khantwal, Abraham et al. have now used techniques called “nuclear magnetic resonance” and "double electron-electron resonance" to investigate how a CLC from a bacterium moves ions. The experiments suggest that when the transporter adopts the outward-facing shape, points on the protein known as Y419 and D417 shift their positions. Chemically linking two regions of the CLC prevented this movement and inhibited the transport of chloride ions across the membrane. Khantwal, Abraham et al. then used a computer simulation to model how the protein changes shape in more detail. This model predicts that two regions of the transporter undergo major rearrangements resulting in a gate-opening motion that widens a passage to allow the chloride ions to bind to the protein. Khantwal, Abraham et al.’s findings will prompt future studies to reveal the other shapes and how CLCs transition between them. DOI:http://dx.doi.org/10.7554/eLife.11189.002
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Affiliation(s)
- Chandra M Khantwal
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Sherwin J Abraham
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Wei Han
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, United States.,College of Medicine, University of Illinois at Urbana-Champaign, Urbana, United States.,Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, United States.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Tao Jiang
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, United States.,College of Medicine, University of Illinois at Urbana-Champaign, Urbana, United States.,Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, United States.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Tanmay S Chavan
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Ricky C Cheng
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Shelley M Elvington
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Corey W Liu
- Stanford Magnetic Resonance Laboratory, Stanford University School of Medicine, Stanford, United States
| | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, United States
| | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, United States
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, United States
| | - Emad Tajkhorshid
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, United States.,College of Medicine, University of Illinois at Urbana-Champaign, Urbana, United States.,Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, United States.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, United States
| | - Merritt Maduke
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
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29
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Kozono H, Matsushita Y, Ogawa N, Kozono Y, Miyabe T, Sekiguchi H, Ichiyanagi K, Okimoto N, Taiji M, Kanagawa O, Sasaki YC. Single-molecule motions of MHC class II rely on bound peptides. Biophys J 2015; 108:350-9. [PMID: 25606683 DOI: 10.1016/j.bpj.2014.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 11/26/2014] [Accepted: 12/02/2014] [Indexed: 11/28/2022] Open
Abstract
The major histocompatibility complex (MHC) class II protein can bind peptides of different lengths in the region outside the peptide-binding groove. Peptide-flanking residues (PFRs) contribute to the binding affinity of the peptide for MHC and change the immunogenicity of the peptide/MHC complex with regard to T cell receptor (TCR). The mechanisms underlying these phenomena are currently unknown. The molecular flexibility of the peptide/MHC complex may be an important determinant of the structures recognized by certain T cells. We used single-molecule x-ray analysis (diffracted x-ray tracking (DXT)) and fluorescence anisotropy to investigate these mechanisms. DXT enabled us to monitor the real-time Brownian motion of the peptide/MHC complex and revealed that peptides without PFRs undergo larger rotational motions than peptides with PFRs. Fluorescence anisotropy further revealed that peptides without PFRs exhibit slightly larger motions on the nanosecond timescale. These results demonstrate that peptides without PFRs undergo dynamic motions in the groove of MHC and consequently are able to assume diverse structures that can be recognized by T cells.
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Affiliation(s)
- Haruo Kozono
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan.
| | - Yufuku Matsushita
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Naoki Ogawa
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Graduate School for Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Yuko Kozono
- Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan
| | - Toshihiro Miyabe
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Hiroshi Sekiguchi
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Kouhei Ichiyanagi
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Noriaki Okimoto
- Computational Biology Research Core, Quantitative Biology Center, RIKEN, Hyogo, Japan
| | - Makoto Taiji
- Computational Biology Research Core, Quantitative Biology Center, RIKEN, Hyogo, Japan
| | - Osami Kanagawa
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Centre International de Recherche en Infectiologie, INSERM U1111, Lyon, France
| | - Yuji C Sasaki
- CREST Sasaki Team, Japan Science and Technology Agency, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan; Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan.
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30
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Oiki S. Channel function reconstitution and re-animation: a single-channel strategy in the postcrystal age. J Physiol 2015; 593:2553-73. [PMID: 25833254 DOI: 10.1113/jp270025] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 03/24/2015] [Indexed: 01/30/2023] Open
Abstract
The most essential properties of ion channels for their physiologically relevant functions are ion-selective permeation and gating. Among the channel species, the potassium channel is primordial and the most ubiquitous in the biological world, and knowledge of this channel underlies the understanding of features of other ion channels. The strategy applied to studying channels changed dramatically after the crystal structure of the potassium channel was resolved. Given the abundant structural information available, we exploited the bacterial KcsA potassium channel as a simple model channel. In the postcrystal age, there are two effective frameworks with which to decipher the functional codes present in the channel structure, namely reconstitution and re-animation. Complex channel proteins are decomposed into essential functional components, and well-examined parts are rebuilt for integrating channel function in the membrane (reconstitution). Permeation and gating are dynamic operations, and one imagines the active channel by breathing life into the 'frozen' crystal (re-animation). Capturing the motion of channels at the single-molecule level is necessary to characterize the behaviour of functioning channels. Advanced techniques, including diffracted X-ray tracking, lipid bilayer methods and high-speed atomic force microscopy, have been used. Here, I present dynamic pictures of the KcsA potassium channel from the submolecular conformational changes to the supramolecular collective behaviour of channels in the membrane. These results form an integrated picture of the active channel and offer insights into the processes underlying the physiological function of the channel in the cell membrane.
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Affiliation(s)
- Shigetoshi Oiki
- Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, Fukui, 910-1193, Japan
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31
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pH-dependent promotion of phospholipid flip-flop by the KcsA potassium channel. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:145-50. [PMID: 25312694 DOI: 10.1016/j.bbamem.2014.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 09/24/2014] [Accepted: 10/01/2014] [Indexed: 11/24/2022]
Abstract
KcsA is a pH-dependent potassium channel that is activated at acidic pH. The channel undergoes global conformational changes upon activation. We hypothesized that the open-close conformational changes of the transmem brane region could promote the flip-flop of phosphoiipids. Based on this hypothesis, we measured the flip-flop ofNBD-labeled phospholipids in KcsA-incorporated proteoliposomes. Both flip and flop rates of ~NBD-PC were significantly enhanced in the presence of KcsA and were several times higher at pH 4.0 than at pH 7.4, suggesting that KcsA promotes the phospholipid flip in a conformation-dependent manner. Phospholipids were nonselectively flipped with respect to the glycerophospholipid structure. In the active state of KcsA channel,tetrabutylammonium locks the channel in the open conformation at acidic pH; however, it did not alter the fliprate of CGNBD-PC. Thus, the open-close transition of the transmembrane region did not affect the flip-flop of phospholipids. In addition, the KcsA mutant that lacked anN-terminal amphipathic helix (MO-helix) was found to show reduced ability to fl ip C6NBD-phospholipids at acidic pH. The closed conformation is stabilized in the absence of MO-heli x, and thus the attenuated flip could be explained by the reduced prevalence of the open conformation.These results suggest that the open conformation of KcsA can disturb the bilayer integrity and facilitate the flip-flop of phospholipids.
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32
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Abstract
Large macromolecular assemblies, so-called molecular machines, are critical to ensuring proper cellular function. Understanding how proper function is achieved at the atomic level is crucial to advancing multiple avenues of biomedical research. Biophysical studies often include X-ray diffraction and cryo-electron microscopy, providing detailed structural descriptions of these machines. However, their inherent flexibility has complicated an understanding of the relation between structure and function. Solution NMR spectroscopy is well suited to the study of such dynamic complexes, and continued developments have increased size boundaries; insights into function have been obtained for complexes with masses as large as 1 MDa. We highlight methyl-TROSY (transverse relaxation optimized spectroscopy) NMR, which enables the study of such large systems, and include examples of applications to several cellular machines. We show how this emerging technique contributes to an understanding of cellular function and the role of molecular plasticity in regulating an array of biochemical activities.
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33
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SUMINO A, YAMAMOTO D, SUMIKAMA T, IWAMOTO M, DEWA T, OIKI S. Structure and Dynamics of Membrane-embedded KcsA Potassium Channel Revealed by Atomic Force Microscopy. ACTA ACUST UNITED AC 2015. [DOI: 10.2142/biophys.55.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Ayumi SUMINO
- PRESTO, Japan Science and Technology Agency (JST)
- Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui
| | | | - Takashi SUMIKAMA
- Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui
| | - Masayuki IWAMOTO
- Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui
| | - Takehisa DEWA
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology
| | - Shigetoshi OIKI
- Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui
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34
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Yamakata A, Shimizu H, Oiki S. Surface-enhanced IR absorption spectroscopy of the KcsA potassium channel upon application of an electric field. Phys Chem Chem Phys 2015; 17:21104-11. [DOI: 10.1039/c5cp02681d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Surface-enhanced IR absorption spectroscopy coupled with an electrochemical system enables the potassium-induced specific structural change of the potassium channel.
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Affiliation(s)
- Akira Yamakata
- Graduate School of Engineering
- Toyota Technological Institute
- Tempaku
- Japan
| | - Hirofumi Shimizu
- Department of Molecular Physiology and Biophysics
- Faculty of Medical Sciences
- University of Fukui
- Fukui 910-1193
- Japan
| | - Shigetoshi Oiki
- Department of Molecular Physiology and Biophysics
- Faculty of Medical Sciences
- University of Fukui
- Fukui 910-1193
- Japan
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35
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Sekiguchi H, Suzuki Y, Nishino Y, Kobayashi S, Shimoyama Y, Cai W, Nagata K, Okada M, Ichiyanagi K, Ohta N, Yagi N, Miyazawa A, Kubo T, Sasaki YC. Real time ligand-induced motion mappings of AChBP and nAChR using X-ray single molecule tracking. Sci Rep 2014; 4:6384. [PMID: 25223459 PMCID: PMC4165275 DOI: 10.1038/srep06384] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 08/29/2014] [Indexed: 11/12/2022] Open
Abstract
We observed the dynamic three-dimensional (3D) single molecule behaviour of acetylcholine-binding protein (AChBP) and nicotinic acetylcholine receptor (nAChR) using a single molecule tracking technique, diffracted X-ray tracking (DXT) with atomic scale and 100 μs time resolution. We found that the combined tilting and twisting motions of the proteins were enhanced upon acetylcholine (ACh) binding. We present the internal motion maps of AChBP and nAChR in the presence of either ACh or α-bungarotoxin (αBtx), with views from two rotational axes. Our findings indicate that specific motion patterns represented as biaxial angular motion maps are associated with channel function in real time and on an atomic scale.
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Affiliation(s)
- Hiroshi Sekiguchi
- 1] CREST Sasaki Team, Japan Science and Technology Agency, The University of Tokyo, #609 Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan [2] Research &Utilization Division, Japan Synchrotron Radiation Research Institute, SPring-8 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Yasuhito Suzuki
- 1] CREST Sasaki Team, Japan Science and Technology Agency, The University of Tokyo, #609 Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan [2] Graduate School of Frontier Sciences, The University of Tokyo, Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan
| | - Yuri Nishino
- 1] Graduate School of Life Sciences, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo, 679-1297, Japan [2] RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Suzuko Kobayashi
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Yoshiko Shimoyama
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Weiyan Cai
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Kenji Nagata
- Graduate School of Frontier Sciences, The University of Tokyo, Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan
| | - Masato Okada
- Graduate School of Frontier Sciences, The University of Tokyo, Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan
| | - Kouhei Ichiyanagi
- 1] CREST Sasaki Team, Japan Science and Technology Agency, The University of Tokyo, #609 Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan [2] Graduate School of Frontier Sciences, The University of Tokyo, Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan
| | - Noboru Ohta
- Research &Utilization Division, Japan Synchrotron Radiation Research Institute, SPring-8 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Naoto Yagi
- 1] CREST Sasaki Team, Japan Science and Technology Agency, The University of Tokyo, #609 Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan [2] Research &Utilization Division, Japan Synchrotron Radiation Research Institute, SPring-8 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Atsuo Miyazawa
- 1] Graduate School of Life Sciences, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo, 679-1297, Japan [2] RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Tai Kubo
- 1] CREST Sasaki Team, Japan Science and Technology Agency, The University of Tokyo, #609 Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan [2] Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan [3] Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Yuji C Sasaki
- 1] CREST Sasaki Team, Japan Science and Technology Agency, The University of Tokyo, #609 Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan [2] Research &Utilization Division, Japan Synchrotron Radiation Research Institute, SPring-8 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan [3] Graduate School of Frontier Sciences, The University of Tokyo, Kiban Bldg., 5-1-5 Kashiwanoha, Kashiwa City, Chiba, 277-8561, Japan
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36
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Hirano M, Okuno D, Onishi Y, Ide T. A single amino acid gates the KcsA channel. Biochem Biophys Res Commun 2014; 450:1537-40. [PMID: 25019991 DOI: 10.1016/j.bbrc.2014.07.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/06/2014] [Indexed: 12/19/2022]
Abstract
The KcsA channel is a proton-activated potassium channel. We have previously shown that the cytoplasmic domain (CPD) acts as a pH-sensor, and the charged states of certain negatively charged amino acids in the CPD play an important role in regulating the pH-dependent gating. Here, we demonstrate the KcsA channel is constitutively open independent of pH upon mutating E146 to a neutrally charged amino acid. In addition, we found that rearrangement of the CPD following this mutation was not large. Our results indicate that minimal rearrangement of the CPD, particularly around E146, is sufficient for opening of the KcsA channel.
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Affiliation(s)
- Minako Hirano
- Bio Photonics Laboratory, The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsu Nishi-ku Hamamatsu, Shizuoka 431-1202, Japan; Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan.
| | - Daichi Okuno
- Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan.
| | - Yukiko Onishi
- Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan.
| | - Toru Ide
- Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka Kita-ku Okayama-shi, Okayama 700-8530, Japan.
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37
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Liang M, Harder R, Robinson IK. Brownian motion studies of viscoelastic colloidal gels by rotational single particle tracking. IUCRJ 2014; 1:172-8. [PMID: 25075336 PMCID: PMC4086434 DOI: 10.1107/s2052252514006022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 03/18/2014] [Indexed: 05/20/2023]
Abstract
Colloidal gels have unique properties due to a complex microstructure which forms into an extended network. Although the bulk properties of colloidal gels have been studied, there has been difficulty correlating those properties with individual colloidal dynamics on the microscale due to the very high viscosity and elasticity of the material. We utilize rotational X-ray tracking (RXT) to investigate the rotational motion of component crystalline colloidal particles in a colloidal gel of alumina and decanoic acid. Our investigation has determined that the high elasticity of the bulk is echoed by a high elasticity experienced by individual colloidal particles themselves but also finds an unexpected high degree of rotational diffusion, indicating a large degree of freedom in the rotational motion of individual colloids even within a tightly bound system.
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Affiliation(s)
- Mengning Liang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Center for Free-Electron Laser Science, Deutsches Elektronensynchrotron, Notkestrasse 85, 22607 Hamburg, Germany
- Correspondence e-mail:
| | - Ross Harder
- Argonne National Lab, Argonne, IL 60439, USA
| | - Ian K. Robinson
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Centre for Nanotechnology, University College, London WC1H 0AH, England
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38
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Ogawa N, Hoshisashi K, Sekiguchi H, Ichiyanagi K, Matsushita Y, Hirohata Y, Suzuki S, Ishikawa A, Sasaki YC. Tracking 3D picometer-scale motions of single nanoparticles with high-energy electron probes. Sci Rep 2014; 3:2201. [PMID: 23868465 PMCID: PMC3715782 DOI: 10.1038/srep02201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 06/26/2013] [Indexed: 11/09/2022] Open
Abstract
We observed the high-speed anisotropic motion of an individual gold nanoparticle in 3D at the picometer scale using a high-energy electron probe. Diffracted electron tracking (DET) using the electron back-scattered diffraction (EBSD) patterns of labeled nanoparticles under wet-SEM allowed us to super-accurately measure the time-resolved 3D motion of individual nanoparticles in aqueous conditions. The highly precise DET data corresponded to the 3D anisotropic log-normal Gaussian distributions over time at the millisecond scale.
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Affiliation(s)
- Naoki Ogawa
- JST/CREST SASAKI-team, Japan Science and Technology Agency, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa City, Chiba, Japan
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39
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Sumino A, Yamamoto D, Iwamoto M, Dewa T, Oiki S. Gating-Associated Clustering-Dispersion Dynamics of the KcsA Potassium Channel in a Lipid Membrane. J Phys Chem Lett 2014; 5:578-84. [PMID: 26276612 DOI: 10.1021/jz402491t] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The KcsA potassium channel is a prototypical channel of bacterial origin, and the mechanism underlying the pH-dependent gating has been studied extensively. With the high-resolution atomic force microscopy (AFM), we have resolved functional open and closed gates of the KcsA channel under the membrane-embedded condition. Here we surprisingly found that the pH-dependent gating of the KcsA channels was associated with clustering-dispersion dynamics. At neutral pH, the resting, closed channels were coalesced, forming nanoclusters. At acidic pH, the open-gated channels were dispersed as singly isolated channels. Time-lapse AFM revealed reversible clustering-dispersion transitions upon pH changes. At acidic equilibrium, a small fraction of the channels was nanoclustered, in which the gate was apparently closed. Thus, it is suggested that opening of the gate and the dispersion are tightly linked. The interplay between the intramolecular conformational change and the supramolecular clustering-dispersion dynamics provides insights into understanding of unprecedented functional cooperativity of channels.
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Affiliation(s)
- Ayumi Sumino
- †PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi-shi, Saitama 332-0012, Japan
- ‡Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuokashimoaizuki, Yoshida-gun, Fukui 910-1193, Japan
| | - Daisuke Yamamoto
- §Department of Applied Physics, Fukuoka University, 8-19-1 Nanakuma, Fukuoka 814-0180, Japan
| | - Masayuki Iwamoto
- ‡Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuokashimoaizuki, Yoshida-gun, Fukui 910-1193, Japan
| | - Takehisa Dewa
- ∥Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Shigetoshi Oiki
- ‡Department of Molecular Physiology and Biophysics, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuokashimoaizuki, Yoshida-gun, Fukui 910-1193, Japan
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40
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Ogawa N, Hirohata Y, Sasaki YC, Ishikawa A. Time-resolved measurement of the three-dimensional motion of gold nanocrystals in water using diffracted electron tracking. Ultramicroscopy 2014; 140:1-8. [PMID: 24561314 DOI: 10.1016/j.ultramic.2014.01.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 12/27/2013] [Accepted: 01/27/2014] [Indexed: 10/25/2022]
Abstract
We introduce diffracted electron tracking (DET), which combines two electron microscopy techniques, electron backscatter diffraction and the use of an environmental cell in a scanning electron microscope to measure changes in nanocrystal-orientation. The accuracy of DET was verified by measuring the motion of a flat gold crystal caused by the rotation or tilting of the specimen stage. DET was applied to measure the motion of semi-fixed gold nanocrystals in various environments. In addition to large motions induced in water environment, DET could detect small differences in the three-dimensional (3D) motion amplitude between vacuum environment and an Ar gas environment. DET promises to be a useful method for measuring the motion of single nanocrystals in various environments. This measuring technique may be used in a wide range of scientific fields; for example, DET may be a prospective method to track the single molecule dynamics of molecules labeled with gold nanocrystals.
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Affiliation(s)
- Naoki Ogawa
- Department of Integrated Science in Physics and Biology, College of Humanities and Sciences, Nihon University, 3-25-40 Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan; Graduate School for Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan.
| | - Yasuhisa Hirohata
- Department of Integrated Science in Physics and Biology, College of Humanities and Sciences, Nihon University, 3-25-40 Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan
| | - Yuji C Sasaki
- Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
| | - Akira Ishikawa
- Department of Physics, College of Humanities and Sciences, Nihon University, 3-25-40 Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan.
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41
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Weingarth M, van der Cruijsen EAW, Ostmeyer J, Lievestro S, Roux B, Baldus M. Quantitative analysis of the water occupancy around the selectivity filter of a K+ channel in different gating modes. J Am Chem Soc 2014; 136:2000-7. [PMID: 24410583 DOI: 10.1021/ja411450y] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recovery in K(+) channels, that is, the transition from the inactivated nonconductive selectivity filter conformation toward the conductive conformation, occurs on a time scale of the order of seconds, which is astonishingly long, given that the structural differences among the filter conformations are faint (<1 Å). Computational studies and electrophysiological measurements suggested that buried water molecules bound behind the selectivity filter are at the origin of the slowness of recovery in K(+) channels. Using a combination of solid-state NMR spectroscopy (ssNMR) and long molecular dynamics simulations, we sketch a high-resolution map of the spatial and temporal distribution of water behind the selectivity filter of a membrane-embedded K(+) channel in two different gating modes. Our study demonstrates that buried water molecules with long residence times are spread all along the rear of the inactivated filter, which explains the recovery kinetics. In contrast, the same region of the structure appears to be dewetted when the selectivity filter is in the conductive state. Using proton-detected ssNMR on fully protonated channels, we demonstrate the presence of a pathway that allows for the interchange of buried and bulk water, as required for a functional influence of buried water on recovery and slow inactivation. Furthermore, we provide direct experimental evidence for the presence of additional ordered water molecules that surround the filter and that are modulated by the channel's gating mode.
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Affiliation(s)
- Markus Weingarth
- NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University , 3584 CH Utrecht, The Netherlands
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42
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Inanobe A, Nakagawa A, Kurachi Y. Conformational changes underlying pore dilation in the cytoplasmic domain of mammalian inward rectifier K+ channels. PLoS One 2013; 8:e79844. [PMID: 24244570 PMCID: PMC3823594 DOI: 10.1371/journal.pone.0079844] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 09/25/2013] [Indexed: 11/18/2022] Open
Abstract
The cytoplasmic domain of inward rectifier K+ (Kir) channels associates with cytoplasmic ligands and undergoes conformational change to control the gate present in its transmembrane domain. Ligand-operated activation appears to cause dilation of the pore at the cytoplasmic domain. However, it is still unclear how the cytoplasmic domain supports pore dilation and how alterations to this domain affect channel activity. In the present study, we focused on 2 spatially adjacent residues, i.e., Glu236 and Met313, of the G protein-gated Kir channel subunit Kir3.2. In the closed state, these pore-facing residues are present on adjacent βD and βH strands, respectively. We mutated both residues, expressed them with the m2-muscarinic receptor in Xenopus oocytes, and measured the acetylcholine-dependent K+ currents. The dose-response curves of the Glu236 mutants tended to be shifted to the right. In comparison, the slopes of the concentration-dependent curves were reduced and the single-channel properties were altered in the Met313 mutants. The introduction of arginine at position 236 conferred constitutive activity and caused a leftward shift in the conductance-voltage relationship. The crystal structure of the cytoplasmic domain of the mutant showed that the arginine contacts the main chains of the βH and βI strands of the adjacent subunit. Because the βH strand forms a β sheet with the βI and βD strands, the immobilization of the pore-forming β sheet appears to confer unique properties to the mutant. These results suggest that the G protein association triggers pore dilation at the cytoplasmic domain in functional channels, and the pore-constituting structural elements contribute differently to these conformational changes.
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Affiliation(s)
- Atsushi Inanobe
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
- Center for Advanced Medical Engineering and Informatics, Osaka University, Suita, Osaka, Japan
- * E-mail: (AI); (YK)
| | - Atsushi Nakagawa
- Laboratory of Supramolecular Crystallography, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Yoshihisa Kurachi
- Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
- Center for Advanced Medical Engineering and Informatics, Osaka University, Suita, Osaka, Japan
- * E-mail: (AI); (YK)
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43
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Ichiyanagi K, Sekiguchi H, Hoshino M, Kajiwara K, Hoshisashi K, Chang JW, Tokue M, Matsushita Y, Nishijima M, Inoue Y, Senba Y, Ohashi H, Ohta N, Yagi N, Sasaki YC. Diffracted X-ray tracking for monitoring intramolecular motion in individual protein molecules using broad band X-ray. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:103701. [PMID: 24182113 DOI: 10.1063/1.4819305] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Diffracted X-ray tracking (DXT) enables the tilting and twisting motions of single protein molecules to be monitored with micro- to milliradian resolution using a highly brilliant X-ray source with a wide energy bandwidth. We have developed a technique to monitor single molecules using gold nanocrystals attached to individual protein molecules using the BL28B2 beamline at SPring-8. In this paper we present the installation of a single toroidal X-ray mirror at BL28B2 to focus X-rays in an energy range of 10-20 keV (ΔE/E = 82% for an X-ray with a wide energy bandwidth). With this beamline we tracked diffraction spots from gold nanocrystals over a wide angle range than that using quasi-monochromatic X-rays. Application of the wide angle DXT technique to biological systems enabled us to observe the on-site motions of single protein molecules that have been functionalized in vivo. We further extend the capability of DXT by observing the fractional tilting and twisting motions of inner proteins under various conditions. As a proof of this methodology and to determine instrumental performance the intramolecular motions of a human serum albumin complex with 2-anthracenecarboxylic acid was investigated using the BL28B2 beamline. The random tilting and twisting intramolecular motions are shown to be directly linked to the movement of individual protein molecules in the buffer solution.
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Affiliation(s)
- Kouhei Ichiyanagi
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 609 Kiban Building 5-1-5 Kashiwanoha, Kahiwashi, Chiba 277-8561, Japan
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44
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Shinohara Y, Watanabe A, Kishimoto H, Amemiya Y. Combined measurement of X-ray photon correlation spectroscopy and diffracted X-ray tracking using pink beam X-rays. JOURNAL OF SYNCHROTRON RADIATION 2013; 20:801-804. [PMID: 23955045 DOI: 10.1107/s090904951301844x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 07/03/2013] [Indexed: 06/02/2023]
Abstract
Combined X-ray photon correlation spectroscopy (XPCS) and diffracted X-ray tracking (DXT) measurements of carbon-black nanocrystals embedded in styrene-butadiene rubber were performed. From the intensity fluctuation of speckle patterns in a small-angle scattering region (XPCS), dynamical information relating to the translational motion can be obtained, and the rotational motion is observed through the changes in the positions of DXT diffraction spots. Graphitized carbon-black nanocrystals in unvulcanized styrene-butadiene rubber showed an apparent discrepancy between their translational and rotational motions; this result seems to support a stress-relaxation model for the origin of super-diffusive particle motion that is widely observed in nanocolloidal systems. Combined measurements using these two techniques will give new insights into nanoscopic dynamics, and will be useful as a microrheology technique.
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Affiliation(s)
- Yuya Shinohara
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.
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45
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Structural changes of the KcsA potassium channel upon application of the electrode potential studied by surface-enhanced IR absorption spectroscopy. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2013.02.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Sekiguchi H, Nakagawa A, Moriya K, Makabe K, Ichiyanagi K, Nozawa S, Sato T, Adachi SI, Kuwajima K, Yohda M, Sasaki YC. ATP dependent rotational motion of group II chaperonin observed by X-ray single molecule tracking. PLoS One 2013; 8:e64176. [PMID: 23734192 PMCID: PMC3666759 DOI: 10.1371/journal.pone.0064176] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 04/08/2013] [Indexed: 11/18/2022] Open
Abstract
Group II chaperonins play important roles in protein homeostasis in the eukaryotic cytosol and in Archaea. These proteins assist in the folding of nascent polypeptides and also refold unfolded proteins in an ATP-dependent manner. Chaperonin-mediated protein folding is dependent on the closure and opening of a built-in lid, which is controlled by the ATP hydrolysis cycle. Recent structural studies suggest that the ring structure of the chaperonin twists to seal off the central cavity. In this study, we demonstrate ATP-dependent dynamics of a group II chaperonin at the single-molecule level with highly accurate rotational axes views by diffracted X-ray tracking (DXT). A UV light-triggered DXT study with caged-ATP and stopped-flow fluorometry revealed that the lid partially closed within 1 s of ATP binding, the closed ring subsequently twisted counterclockwise within 2–6 s, as viewed from the top to bottom of the chaperonin, and the twisted ring reverted to the original open-state with a clockwise motion. Our analyses clearly demonstrate that the biphasic lid-closure process occurs with unsynchronized closure and a synchronized counterclockwise twisting motion.
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Affiliation(s)
- Hiroshi Sekiguchi
- CREST Sasaki Team, Japan Science and Technology Agency, The University of Tokyo, Kashiwa city, Chiba, Japan
- Japan Synchrotron Radiation Research Institute, Sayo, Hyogo, Japan
- Foundation Advanced Technology Institute, Tokyo, Japan
| | - Ayumi Nakagawa
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Kazuki Moriya
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Koki Makabe
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institute of Natural Sciences, Okazaki, Japan
- Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (Sokendai), Okazaki, Japan
| | - Kouhei Ichiyanagi
- CREST Sasaki Team, Japan Science and Technology Agency, The University of Tokyo, Kashiwa city, Chiba, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa city, Chiba, Japan
| | - Shunsuke Nozawa
- High Energy Accelerator Research Organization, Tsukuba, Ibaraki, Japan
| | - Tokushi Sato
- High Energy Accelerator Research Organization, Tsukuba, Ibaraki, Japan
| | - Shin-ichi Adachi
- High Energy Accelerator Research Organization, Tsukuba, Ibaraki, Japan
- PREST, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Kunihiro Kuwajima
- Okazaki Institute for Integrative Bioscience and Institute for Molecular Science, National Institute of Natural Sciences, Okazaki, Japan
- Department of Functional Molecular Science, School of Physical Sciences, Graduate University for Advanced Studies (Sokendai), Okazaki, Japan
| | - Masafumi Yohda
- Foundation Advanced Technology Institute, Tokyo, Japan
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Yuji C. Sasaki
- CREST Sasaki Team, Japan Science and Technology Agency, The University of Tokyo, Kashiwa city, Chiba, Japan
- Japan Synchrotron Radiation Research Institute, Sayo, Hyogo, Japan
- Foundation Advanced Technology Institute, Tokyo, Japan
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa city, Chiba, Japan
- * E-mail:
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47
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Probing the energy landscape of activation gating of the bacterial potassium channel KcsA. PLoS Comput Biol 2013; 9:e1003058. [PMID: 23658510 PMCID: PMC3642040 DOI: 10.1371/journal.pcbi.1003058] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 03/27/2013] [Indexed: 11/19/2022] Open
Abstract
The bacterial potassium channel KcsA, which has been crystallized in several conformations, offers an ideal model to investigate activation gating of ion channels. In this study, essential dynamics simulations are applied to obtain insights into the transition pathways and the energy profile of KcsA pore gating. In agreement with previous hypotheses, our simulations reveal a two phasic activation gating process. In the first phase, local structural rearrangements in TM2 are observed leading to an intermediate channel conformation, followed by large structural rearrangements leading to full opening of KcsA. Conformational changes of a highly conserved phenylalanine, F114, at the bundle crossing region are crucial for the transition from a closed to an intermediate state. 3.9 µs umbrella sampling calculations reveal that there are two well-defined energy barriers dividing closed, intermediate, and open channel states. In agreement with mutational studies, the closed state was found to be energetically more favorable compared to the open state. Further, the simulations provide new insights into the dynamical coupling effects of F103 between the activation gate and the selectivity filter. Investigations on individual subunits support cooperativity of subunits during activation gating.
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48
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Sumino A, Sumikama T, Iwamoto M, Dewa T, Oiki S. The open gate structure of the membrane-embedded KcsA potassium channel viewed from the cytoplasmic side. Sci Rep 2013; 3:1063. [PMID: 23323207 PMCID: PMC3545221 DOI: 10.1038/srep01063] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 12/06/2012] [Indexed: 01/24/2023] Open
Abstract
Crystallographic studies of channel proteins have provided insight into the molecular mechanisms of ion channels, even though these structures are obtained in the absence of the membrane and some structural portions have remained unsolved. Here we report the gating structure of the membrane-embedded KcsA potassium channel using atomic force microscopy (AFM). The activation gate of the KcsA channel is located on the intracellular side, and the cytoplasmic domain was truncated to clear the view of this location. Once opened, the individual subunits in the tetramer were resolved with the pore open at the center. Furthermore, AFM was able to capture the previously unsolved bulge helix at the entrance. A molecular dynamics simulation revealed that the bulge helices fluctuated dramatically at the open entryway. This dynamic behavior was observed as vigorous open-channel noise in the single-channel current recordings. The role of the bulge helices in the open gate structure is discussed.
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Affiliation(s)
- Ayumi Sumino
- Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
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49
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Amphipathic antenna of an inward rectifier K+ channel responds to changes in the inner membrane leaflet. Proc Natl Acad Sci U S A 2012; 110:749-54. [PMID: 23267068 DOI: 10.1073/pnas.1217323110] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Membrane lipids modulate the function of membrane proteins. In the case of ion channels, they bias the gating equilibrium, although the underlying mechanism has remained elusive. Here we demonstrate that the N-terminal segment (M0) of the KcsA potassium channel mediates the effect of changes in the lipid milieu on channel gating. The M0 segment is a membrane-anchored amphipathic helix, bearing positively charged residues. In asymmetric membranes, the M0 helix senses the presence of negatively charged phospholipids on the inner leaflet. Upon gating, the M0 helix revolves around the axis of the helix on the membrane surface, inducing the positively charged residues to interact with the negative head groups of the lipids so as to stabilize the open conformation (i.e., the "roll-and-stabilize model"). The M0 helix is thus a charge-sensitive "antenna," capturing temporary changes in lipid composition in the fluidic membrane. This unique type of sensory device may be shared by various types of membrane proteins.
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50
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Abstract
Lipid bilayers are natural barriers of biological cells and cellular compartments. Membrane proteins integrated in biological membranes enable vital cell functions such as signal transduction and the transport of ions or small molecules. In order to determine the activity of a protein of interest at defined conditions, the membrane protein has to be integrated into artificial lipid bilayers immobilized on a surface. For the fabrication of such biosensors expertise is required in material science, surface and analytical chemistry, molecular biology and biotechnology. Specifically, techniques are needed for structuring surfaces in the micro- and nanometer scale, chemical modification and analysis, lipid bilayer formation, protein expression, purification and solubilization, and most importantly, protein integration into engineered lipid bilayers. Electrochemical and optical methods are suitable to detect membrane activity-related signals. The importance of structural knowledge to understand membrane protein function is obvious. Presently only a few structures of membrane proteins are solved at atomic resolution. Functional assays together with known structures of individual membrane proteins will contribute to a better understanding of vital biological processes occurring at biological membranes. Such assays will be utilized in the discovery of drugs, since membrane proteins are major drug targets.
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