1
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Lamichhane S, Timalsina R, Schultz C, Fescenko I, Ambal K, Liou SH, Lai RY, Laraoui A. Nitrogen-Vacancy Magnetic Relaxometry of Nanoclustered Cytochrome C Proteins. NANO LETTERS 2024; 24:873-880. [PMID: 38207217 DOI: 10.1021/acs.nanolett.3c03843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Nitrogen-vacancy (NV) magnetometry offers an alternative tool to detect paramagnetic centers in cells with a favorable combination of magnetic sensitivity and spatial resolution. Here, we employ NV magnetic relaxometry to detect cytochrome C (Cyt-C) nanoclusters. Cyt-C is a water-soluble protein that plays a vital role in the electron transport chain of mitochondria. Under ambient conditions, the heme group in Cyt-C remains in the Fe3+ state, which is paramagnetic. We vary the concentration of Cyt-C from 6 to 54 μM and observe a reduction of the NV spin-lattice relaxation time (T1) from 1.2 ms to 150 μs, which is attributed to the spin noise originating from the Fe3+ spins. NV T1 imaging of Cyt-C drop-casted on a nanostructured diamond chip allows us to detect the relaxation rates from the adsorbed Fe3+ within Cyt-C.
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Affiliation(s)
- Suvechhya Lamichhane
- Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Rupak Timalsina
- Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Cody Schultz
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Ilja Fescenko
- Laser Center, University of Latvia, Riga, LV-1004, Latvia
| | - Kapildeb Ambal
- Department of Mathematics, Statistics, and Physics, Wichita State University, Wichita, Kansas 67260, United States
| | - Sy-Hwang Liou
- Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Rebecca Y Lai
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Abdelghani Laraoui
- Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
- Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
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2
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Pijning T, Vujičić‐Žagar A, van der Laan J, de Jong RM, Ramirez‐Palacios C, Vente A, Edens L, Dijkstra BW. Structural and time-resolved mechanistic investigations of protein hydrolysis by the acidic proline-specific endoprotease from Aspergillus niger. Protein Sci 2024; 33:e4856. [PMID: 38059672 PMCID: PMC10731622 DOI: 10.1002/pro.4856] [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: 06/14/2023] [Revised: 11/16/2023] [Accepted: 12/04/2023] [Indexed: 12/08/2023]
Abstract
Proline-specific endoproteases have been successfully used in, for example, the in-situ degradation of gluten, the hydrolysis of bitter peptides, the reduction of haze during beer production, and the generation of peptides for mass spectroscopy and proteomics applications. Here we present the crystal structure of the extracellular proline-specific endoprotease from Aspergillus niger (AnPEP), a member of the S28 peptidase family with rarely observed true proline-specific endoprotease activity. Family S28 proteases have a conventional Ser-Asp-His catalytic triad, but their oxyanion-stabilizing hole shows a glutamic acid, an amino acid not previously observed in this role. Since these enzymes have an acidic pH optimum, the presence of a glutamic acid in the oxyanion hole may confine their activity to an acidic pH. Yet, considering the presence of the conventional catalytic triad, it is remarkable that the A. niger enzyme remains active down to pH 1.5. The determination of the primary cleavage site of cytochrome c along with molecular dynamics-assisted docking studies indicate that the active site pocket of AnPEP can accommodate a reverse turn of approximately 12 amino acids with proline at the S1 specificity pocket. Comparison with the structures of two S28-proline-specific exopeptidases reveals not only a more spacious active site cavity but also the absence of any putative binding sites for amino- and carboxyl-terminal residues as observed in the exopeptidases, explaining AnPEP's observed endoprotease activity.
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Affiliation(s)
- Tjaard Pijning
- Biomolecular X‐ray Crystallography, Groningen Biomolecular Sciences and Biotechnology Institute (GBB)University of GroningenGroningenThe Netherlands
| | - Andreja Vujičić‐Žagar
- Biomolecular X‐ray Crystallography, Groningen Biomolecular Sciences and Biotechnology Institute (GBB)University of GroningenGroningenThe Netherlands
| | | | | | | | - Andre Vente
- Taste, Texture and HealthDSM‐FirmenichDelftThe Netherlands
| | - Luppo Edens
- Taste, Texture and HealthDSM‐FirmenichDelftThe Netherlands
| | - Bauke W. Dijkstra
- Biomolecular X‐ray Crystallography, Groningen Biomolecular Sciences and Biotechnology Institute (GBB)University of GroningenGroningenThe Netherlands
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3
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Suzuki M, Tsuchiko A, Tanaka Y, Matubayasi N, Mogami G, Uozumi N, Takahashi S. Hyper-mobile Water and Raman 2900 cm -1 Peak Band of Water Observed around Backbone Phosphates of Double Stranded DNA by High-Resolution Spectroscopies and MD Structural Feature Analysis of Water. J Phys Chem B 2023; 127:285-299. [PMID: 36573838 DOI: 10.1021/acs.jpcb.2c06952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
High-resolution measurements of microwave dielectric relaxation and Raman spectroscopies for waters in double-stranded (ds) 10-mer DNA solution revealed the presence of hyper-mobile water (HMW) and a marked OH stretching band appearing in the range from 2500 to 3100 cm-1, here called the LA band, at the low wavenumber tail of the major OH stretching band of water. Quantitation of the Raman scattering intensity for ds 10-mer DNA in phosphate or tris(hydroxymethyl)aminomethane (TRIS) buffers showed that the LA band was formed by 2000-3000 water molecules per ds 10-mer DNA, indicating collective OH stretching vibrations of water molecules around the backbone phosphate oxygen atoms. The LA band intensity of ds 10-mer DNA in 10 mM TRIS increased and decreased by 30% with the addition of 2 mM MgCl2 and 2 mM CaCl2, respectively. The LA band intensity and the effect of adding Mg(II) or Ca(II) ions to the band intensity were maintained in the presence of 0.14 M KCl; however, the changes induced by the divalent cations were reduced by half. Molecular dynamics calculations of water molecules around the backbone phosphate groups of ds 10-mer DNA indicate the presence of high-density water and broad regions of fluctuating water density, suggesting that they correspond to HMW and the LA band, respectively.
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Affiliation(s)
- Makoto Suzuki
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira Aobaku, Sendai980-8577, Japan.,Graduate School of Engineering, Tohoku University, 6-6 Aoba Aramaki Aobaku, Sendai980-8579, Japan
| | - Akira Tsuchiko
- Graduate School of Engineering, Tohoku University, 6-6 Aoba Aramaki Aobaku, Sendai980-8579, Japan
| | - Yoshiyuki Tanaka
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, 180 Nishihamahoji Yamashirocho, Tokushima770-8514, Japan
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka560-8531, Japan
| | - George Mogami
- Graduate School of Engineering, Tohoku University, 6-6 Aoba Aramaki Aobaku, Sendai980-8579, Japan
| | - Nobuyuki Uozumi
- Graduate School of Engineering, Tohoku University, 6-6 Aoba Aramaki Aobaku, Sendai980-8579, Japan
| | - Satoshi Takahashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira Aobaku, Sendai980-8577, Japan
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4
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Pandey P, Bhattarai N, Su L, Wang X, Leng F, Gerst-man B, Chapagain PP, He J. Detecting Individual Proteins and Their Surface Charge Variations in Solution by the Potentiometric Nanoimpact Method. ACS Sens 2022; 7:555-563. [PMID: 35060380 PMCID: PMC10631516 DOI: 10.1021/acssensors.1c02385] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Label-free detection and analysis of proteins in their natural form and their dynamic interactions with substrates at the single-molecule level are important for both fundamental studies and various applications. Herein, we demonstrate a simple potentiometric method to achieve this goal by detecting the native charge of protein in solution by utilizing the principle of single-entity electrochemistry techniques. When a charged protein moves near the vicinity of a floating carbon nanoelectrode connected to a high-impedance voltage meter, the distinct local electrostatic potential changes induced by the transient collision event of protein, also called the "nanoimpact" event, can be captured by the nanoelectrode as a potential probe. This potentiometric method is highly sensitive for charged proteins, and low-molecular-weight proteins less than 10 kDa can be detected in low-salt-concentration electrolytes. By analyzing the shape and magnitude of the recorded time-resolved potential change and its time derivative, we can reveal the charge and motion of the protein in the nonspecific protein-surface interaction event. The charge polarity variations of the proteins at different pH values were also successfully probed. Compared with synthetic spherical nanoparticles, the statistical analysis of many single-molecule nanoimpact events revealed a large variation in the recorded transient potential signals, which may be attributed to the intrinsic protein dynamics and surface charge heterogeneity, as suggested by the finite element method and molecular dynamic simulations.
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Affiliation(s)
- Popular Pandey
- Physics Department, Florida International University, Miami, Florida, 33199, USA
| | - Nisha Bhattarai
- Physics Department, Florida International University, Miami, Florida, 33199, USA
| | - Linjia Su
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA
| | - Xuewen Wang
- Physics Department, Florida International University, Miami, Florida, 33199, USA
| | - Fenfei Leng
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, Florida, 33199, USA
| | - Bernard Gerst-man
- Physics Department, Florida International University, Miami, Florida, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, Florida, 33199, USA
| | - Prem P. Chapagain
- Physics Department, Florida International University, Miami, Florida, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, Florida, 33199, USA
| | - Jin He
- Physics Department, Florida International University, Miami, Florida, 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, Florida, 33199, USA
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5
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Suzuki M, Mogami G, Ohsugi H, Watanabe T, Matubayasi N. Physical driving force of actomyosin motility based on the hydration effect. Cytoskeleton (Hoboken) 2017; 74:512-527. [PMID: 29087038 DOI: 10.1002/cm.21417] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/24/2017] [Accepted: 10/25/2017] [Indexed: 01/20/2023]
Abstract
We propose a driving force hypothesis based on previous thermodynamics, kinetics and structural data as well as additional experiments and calculations presented here on water-related phenomena in the actomyosin systems. Although Szent-Györgyi pointed out the importance of water in muscle contraction in 1951, few studies have focused on the water science of muscle because of the difficulty of analyzing hydration properties of the muscle proteins, actin, and myosin. The thermodynamics and energetics of muscle contraction are linked to the water-mediated regulation of protein-ligand and protein-protein interactions along with structural changes in protein molecules. In this study, we assume the following two points: (1) the periodic electric field distribution along an actin filament (F-actin) is unidirectionally modified upon binding of myosin subfragment 1 (M or myosin S1) with ADP and inorganic phosphate Pi (M.ADP.Pi complex) and (2) the solvation free energy of myosin S1 depends on the external electric field strength and the solvation free energy of myosin S1 in close proximity to F-actin can become the potential force to drive myosin S1 along F-actin. The first assumption is supported by integration of experimental reports. The second assumption is supported by model calculations utilizing molecular dynamics (MD) simulation to determine solvation free energies of a small organic molecule and two small proteins. MD simulations utilize the energy representation method (ER) and the roughly proportional relationship between the solvation free energy and the solvent-accessible surface area (SASA) of the protein. The estimated driving force acting on myosin S1 is as high as several piconewtons (pN), which is consistent with the experimentally observed force.
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Affiliation(s)
- Makoto Suzuki
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan.,Biological and Molecular Dynamics, Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, 980-8577, Japan.,Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
| | - George Mogami
- Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
| | - Hideyuki Ohsugi
- Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
| | - Takahiro Watanabe
- Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, 560-8531, Japan.,Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Katsura, Kyoto, 615-8520, Japan
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6
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Masanari M, Fujii S, Kawahara K, Oki H, Tsujino H, Maruno T, Kobayashi Y, Ohkubo T, Wakai S, Sambongi Y. Comparative study on stabilization mechanism of monomeric cytochrome c5 from deep-sea piezophilic Shewanella violacea. Biosci Biotechnol Biochem 2016; 80:2365-2370. [DOI: 10.1080/09168451.2016.1232155] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
Monomeric cytochrome c5 from deep-sea piezophilic Shewanella violacea (SVcytc5) was stable against heat and denaturant compared with the homologous protein from shallow-sea piezo-sensitive Shewanella livingstonensis (SLcytc5). Here, the SVcytc5 crystal structure revealed that the Lys-50 side chain on the flexible loop formed a hydrogen bond with heme whereas that of corresponding hydrophobic Leu-50 could not form such a bond in SLcytc5, which appeared to be one of possible factors responsible for the difference in stability between the two proteins. This structural insight was confirmed by a reciprocal mutagenesis study on the thermal stability of these two proteins. As SVcytc5 was isolated from a deep-sea piezophilic bacterium, the present comparative study indicates that adaptation of monomeric SVcytc5 to high pressure environments results in stabilization against heat.
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Affiliation(s)
- Misa Masanari
- Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan
| | - Sotaro Fujii
- Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan
| | - Kazuki Kawahara
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Hiroya Oki
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Hirofumi Tsujino
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Takahiro Maruno
- Graduate School of Engineering, Osaka University, Suita, Japan
| | - Yuji Kobayashi
- Graduate School of Engineering, Osaka University, Suita, Japan
| | - Tadayasu Ohkubo
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
| | - Satoshi Wakai
- Graduate School of Science Technology and Innovation, Kobe University, Kobe, Japan
| | - Yoshihiro Sambongi
- Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan
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7
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Suzuki M, Imao A, Mogami G, Chishima R, Watanabe T, Yamaguchi T, Morimoto N, Wazawa T. Strong Dependence of Hydration State of F-Actin on the Bound Mg(2+)/Ca(2+) Ions. J Phys Chem B 2016; 120:6917-28. [PMID: 27332748 DOI: 10.1021/acs.jpcb.6b02584] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Understanding of the hydration state is an important issue in the chemomechanical energetics of versatile biological functions of polymerized actin (F-actin). In this study, hydration-state differences of F-actin by the bound divalent cations are revealed through precision microwave dielectric relaxation (DR) spectroscopy. G- and F-actin in Ca- and Mg-containing buffer solutions exhibit dual hydration components comprising restrained water with DR frequency f2 (<fw: DR frequency of bulk solvent, 17 GHz at 20 °C) and hypermobile water (HMW) with DR frequency f1 (>fw). The hydration state of F-actin is strongly dependent on the ionic composition. In every buffer tested, the HMW signal Dhyme (≡ (f1 - fw)δ1/(fwδw)) of F-actin is stronger than that of G-actin, where δw is DR-amplitude of bulk solvent and δ1 is that of HMW in a fixed-volume ellipsoid containing an F-actin and surrounding water in solution. Dhyme value of F-actin in Ca2.0-buffer (containing 2 mM Ca(2+)) is markedly higher than in Mg2.0-buffer (containing 2 mM Mg(2+)). Moreover, in the presence of 2 mM Mg(2+), the hydration state of F-actin is changed by adding a small fraction of Ca(2+) (∼0.1 mM) and becomes closer to that of the Ca-bound form in Ca2.0-buffer. This is consistent with the results of the partial specific volume and the Cotton effect around 290 nm in the CD spectra, indicating a change in the tertiary structure and less apparent change in the secondary structure of actin. The number of restrained water molecules per actin (N2) is estimated to be 1600-2100 for Ca2.0- and F-buffer and ∼2500 for Mg2.0-buffer at 10-15 °C. These numbers are comparable to those estimated from the available F-actin atomic structures as in the first water layer. The number of HMW molecules is roughly explained by the volume between the equipotential surface of -kT/2e and the first water layer of the actin surface by solving the Poisson-Boltzmann equation using UCSF Chimera.
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Affiliation(s)
- Makoto Suzuki
- Department of Materials Processing, Graduate School of Engineering, Tohoku University , 6-6-02 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan.,Frontier Research Institute for Interdisciplinary Sciences, Tohoku University , Sendai, Miyagi 980-8578, Japan
| | - Asato Imao
- Department of Materials Processing, Graduate School of Engineering, Tohoku University , 6-6-02 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - George Mogami
- Department of Materials Processing, Graduate School of Engineering, Tohoku University , 6-6-02 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan.,Frontier Research Institute for Interdisciplinary Sciences, Tohoku University , Sendai, Miyagi 980-8578, Japan
| | - Ryotaro Chishima
- Department of Materials Processing, Graduate School of Engineering, Tohoku University , 6-6-02 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Takahiro Watanabe
- Department of Materials Processing, Graduate School of Engineering, Tohoku University , 6-6-02 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Takaya Yamaguchi
- Department of Materials Processing, Graduate School of Engineering, Tohoku University , 6-6-02 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Nobuyuki Morimoto
- Department of Materials Processing, Graduate School of Engineering, Tohoku University , 6-6-02 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Tetsuichi Wazawa
- Department of Biomolecular Science and Engineering, The Institute of Scientific and Industrial Research, Osaka University , Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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8
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Wazawa T, Morimoto N, Nagai T, Suzuki M. Rotational motion of rhodamine 6G tethered to actin through oligo(ethylene glycol) linkers studied by frequency-domain fluorescence anisotropy. Biophys Physicobiol 2015; 12:87-102. [PMID: 27493858 PMCID: PMC4736842 DOI: 10.2142/biophysico.12.0_87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 11/02/2015] [Indexed: 12/01/2022] Open
Abstract
Investigation of the rotational motion of a fluorescent probe tethered to a protein helps to elucidate the local properties of the solvent and protein near the conjugation site of the probe. In this study, we have developed an instrument for frequency-domain fluorescence (FDF) anisotropy measurements, and studied how the local properties around a protein, actin, can be elucidated from the rotational motion of a dye tethered to actin. Rhodamine 6G (R6G) was attached to Cys-374 using newly-synthesized R6G-maleimide with three different oligo(ethylene glycol) (OEG) linker lengths. The time-resolved anisotropy decay of R6G tethered to G-actin was revealed to be a combination of the two modes of the wobbling motion of R6G and the tumbling motion of G-actin. The rotational diffusion coefficient (RDC) of R6G wobbling was ~0.1 ns−1 at 20°C and increased with OEG linker length. The use of the three R6G-actin conjugates of different linker lengths was useful to not only figure out the linker length dependence of the rotational motion of R6G but also validate the analyses. In the presence of a cosolvent of glycerol, although the tumbling motion of G-actin was retarded in response to the bulk viscosity, the wobbling motion of R6G tethered to actin exhibited an increase of RDC as glycerol concentration increased. This finding suggests an intricate relationship between the fluid properties of the bulk solvent and the local environment around actin.
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Affiliation(s)
- Tetsuichi Wazawa
- Department of Biomolecular Science and Engineering, Institute for Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan; Department of Materials Processing, Graduate School of Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Nobuyuki Morimoto
- Department of Materials Processing, Graduate School of Tohoku University, Sendai, Miyagi 980-8579, Japan
| | - Takeharu Nagai
- Department of Biomolecular Science and Engineering, Institute for Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Makoto Suzuki
- Department of Materials Processing, Graduate School of Tohoku University, Sendai, Miyagi 980-8579, Japan
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9
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Soffer JB, Schweitzer-Stenner R. Near-exact enthalpy–entropy compensation governs the thermal unfolding of protonation states of oxidized cytochrome c. J Biol Inorg Chem 2014; 19:1181-94. [DOI: 10.1007/s00775-014-1174-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 06/16/2014] [Indexed: 11/24/2022]
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10
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Suzuki M. What is “hypermobile” water?: detected in alkali halide, adenosine phosphate, and F-actin solutions by high-resolution microwave dielectric spectroscopy. PURE APPL CHEM 2014. [DOI: 10.1515/pac-2014-5024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Experimental observation by high-resolution microwave dielectric spectroscopy of hydration properties of alkali halide ions, adenosine phosphate ions, and F-actin revealed the existence of hypermobile water (HMW) molecules around those solutes. To understand the molecular process of HMW, two theoretical approaches are reviewed here. One is based on a statistical mechanical approach to analyze the rotational freedom of water molecules around a charged particle. Another approach reports direct calculation of dielectric relaxation process of water molecules around an ion. Experimentally observed HMW molecules are theoretically explained with the significance of multi-correlations among an ion and water molecules.
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11
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Mogami G, Miyazaki T, Wazawa T, Matubayasi N, Suzuki M. Anion-Dependence of Fast Relaxation Component in Na-, K-Halide Solutions at Low Concentrations Measured by High-Resolution Microwave Dielectric Spectroscopy. J Phys Chem A 2013; 117:4851-62. [DOI: 10.1021/jp4012119] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- George Mogami
- Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Takashi Miyazaki
- Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Tetsuichi Wazawa
- Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Nobuyuki Matubayasi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Makoto Suzuki
- Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
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