1
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Mostafa HIA. Detection of bacteriorhodopsin trimeric rotation at thermal phase transitions of purple membrane in suspension. Biophys Chem 2023; 300:107074. [PMID: 37421867 DOI: 10.1016/j.bpc.2023.107074] [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: 04/20/2023] [Revised: 06/24/2023] [Accepted: 07/02/2023] [Indexed: 07/10/2023]
Abstract
Bacteriorhodopsin (bR) of purple membrane (PM) is a retinal protein that forms aggregates in the form of trimers constituting, together with archaeal lipids, the crystalline structure of PM. The rotary motion of bR inside PM may be pertinent in understanding the essence of the crystalline lattice. An attempt has been made to determine the rotation of bR trimers which has been found to be detected solely at thermal phase transitions of PM, namely lipid, crystalline lattice and protein melting phase transitions. The temperature dependences of dielectric versus electronic absorption spectra of bR have been determined. The results suggest that the rotation of bR trimers, together with concomitant bending of PM, are most likely brought by structural changes in bR which might be driven by retinal isomerization and mediated by lipid. The rupturing of the lipid-protein contact might consequently lead to rotation of trimers associated with bending, curling or vesicle formation of PM. So the retinal reorientation may underlie the concomitant rotation of trimers. Most importantly, rotation of trimers might play a role, in terms of the essence of the crystalline lattice, in the functional activity of bR and may serve physiological relevance.
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Affiliation(s)
- Hamdy I A Mostafa
- Department of Biophysics, Faculty of Science, Cairo University, 11757 Giza, Egypt.
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2
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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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3
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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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4
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Kobayashi S, Fujii S, Koga A, Wakai S, Matubayasi N, Sambongi Y. Pseudomonas aeruginosa cytochrome c551 denaturation by five systematic urea derivatives that differ in the alkyl chain length. Biosci Biotechnol Biochem 2017; 81:1274-1278. [DOI: 10.1080/09168451.2017.1303361] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Abstract
Reversible denaturation of Pseudomonas aeruginosa cytochrome c551 (PAc551) could be followed using five systematic urea derivatives that differ in the alkyl chain length, i.e. urea, N-methylurea (MU), N-ethylurea (EU), N-propylurea (PU), and N-butylurea (BU). The BU concentration was the lowest required for the PAc551 denaturation, those of PU, EU, MU, and urea being gradually higher. Furthermore, the accessible surface area difference upon PAc551 denaturation caused by BU was found to be the highest, those by PU, EU, MU, and urea being gradually lower. These findings indicate that urea derivatives with longer alkyl chains are stronger denaturants. In this study, as many as five systematic urea derivatives could be applied for the reversible denaturation of a single protein, PAc551, for the first time, and the effects of the alkyl chain length on protein denaturation were systematically verified by means of thermodynamic parameters.
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Affiliation(s)
- Shinya Kobayashi
- Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan
| | - Sotaro Fujii
- Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan
| | - Aya Koga
- Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan
| | - Satoshi Wakai
- Graduate School of Science Technology and Innovation, Kobe University, Kobe, Japan
| | - Nobuyuki Matubayasi
- Graduate School of Engineering Science, Osaka University, Osaka, Japan
- Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Kyoto, Japan
| | - Yoshihiro Sambongi
- Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan
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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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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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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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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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9
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Miyashita Y, Wazawa T, Mogami G, Takahashi S, Sambongi Y, Suzuki M. Hydration-state change of horse heart cytochrome c corresponding to trifluoroacetic-acid-induced unfolding. Biophys J 2013; 104:163-72. [PMID: 23332069 DOI: 10.1016/j.bpj.2012.11.3825] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 11/07/2012] [Accepted: 11/29/2012] [Indexed: 12/14/2022] Open
Abstract
We investigate the hydration state of horse-heart cytochrome c (hh cyt c) in the unfolding process induced by trifluoroacetic acid (TFA). The conformation of hh cyt c changes from the native (N) state (2.9 < pH < 6.0) to the acid-unfolded (U(A)) state (1.7 < pH < 2.0) to the acid-induced molten globule (A) state (pH ∼1.2). Hydration properties of hh cyt c during this process are measured at 20°C by high-resolution dielectric relaxation (DR) spectroscopy, UV-vis absorbance, and circular dichroism spectroscopy. Constrained water of hh cyt c is observed at every pH as an ∼5-GHz Debye component (DC) (DR time, τ(D) ∼30 ps) and its DR amplitude (DRA) is increased by 77% upon N-to-U(A) transition, when pH changes from 6.0 to 2.0. Even in the N state, the DRA of the constrained-water component is found to be increased by 22% with decreasing pH from 6.0 to 2.9, suggesting an increase in the accessible surface area of native hh cyt c. Moreover, hypermobile water around native hh cyt c is detected at pH 6.0 as a 19-GHz DC (τ(D) ∼ 8.4 ps <τ(DW) = 9.4 ps), but is not found at other pH values. The DRA signal of constrained water is found to return to the pH 2.9 (N-state) level upon U(A)-to-A transition. Fast-response water (slightly slower than bulk) around A-state hh cyt c is detected at pH 1.2, and this suggests some accumulation of TFA(-) ions around the peptide chain. Thus, this high-resolution DR spectroscopy study reveals that hh cyt c exhibits significant hydration-state change in the TFA-unfolding process.
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Affiliation(s)
- Yusuke Miyashita
- Department of Materials Processing, Graduate School of Engineering, Tohoku University, Sendai, Miyagi, Japan
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Kubota Y, Yoshimori A, Matubayasi N, Suzuki M, Akiyama R. Molecular dynamics study of fast dielectric relaxation of water around a molecular-sized ion. J Chem Phys 2012; 137:224502. [DOI: 10.1063/1.4769972] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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11
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Rajapandian V, Subramanian V. Calculations on the Structure and Spectral Properties of Cytochrome c551 Using DFT and ONIOM Methods. J Phys Chem A 2011; 115:2866-76. [DOI: 10.1021/jp110983v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- V. Rajapandian
- Chemical Laboratory, Central Leather Research Institute, Council of Scientific and Industrial Research, Adyar, Chennai 600 020, India
| | - V. Subramanian
- Chemical Laboratory, Central Leather Research Institute, Council of Scientific and Industrial Research, Adyar, Chennai 600 020, India
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Mogami G, Wazawa T, Morimoto N, Kodama T, Suzuki M. Hydration properties of adenosine phosphate series as studied by microwave dielectric spectroscopy. Biophys Chem 2010; 154:1-7. [PMID: 21167630 DOI: 10.1016/j.bpc.2010.11.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2010] [Revised: 11/13/2010] [Accepted: 11/21/2010] [Indexed: 10/18/2022]
Abstract
Hydration properties of adenine nucleotides and orthophosphate (Pi) in aqueous solutions adjusted to pH=8 with NaOH were studied by high-resolution microwave dielectric relaxation (DR) spectroscopy at 20 °C. The dielectric spectra were analyzed using a mixture theory combined with a least-squares Debye decomposition method. Solutions of Pi and adenine nucleotides showed qualitatively similar dielectric properties described by two Debye components. One component was characterized by a relaxation frequency (f(c)=18.8-19.7 GHz) significantly higher than that of bulk water (17 GHz) and the other by a much lower f(c) (6.4-7.6 GHz), which are referred to here as hyper-mobile water and constrained water, respectively. By contrast, a hydration shell of only the latter type was found for adenosine (f(c)~6.7 GHz). The present results indicate that phosphoryl groups are mostly responsible for affecting the structure of the water surrounding the adenine nucleotides by forming one constrained water layer and an additional three or four layers of hyper-mobile water.
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Affiliation(s)
- George Mogami
- Laboratory of Biomaterials Physical Chemistry, Department of Materials Processing, Graduate School of Engineering, Tohoku University, CREST/JST, 6-6-02 Aoba, Aramaki-aza, Aoba-Ku, Sendai, Miyagi 980-8579, Japan
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