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Longhena F, Boujebene R, Brembati V, Sandre M, Bubacco L, Abbate S, Longhi G, Bellucci A. Nanorod-associated plasmonic circular dichroism monitors the handedness and composition of α-synuclein fibrils from Parkinson's disease models and post-mortem brain. NANOSCALE 2024. [PMID: 39318230 DOI: 10.1039/d4nr03002h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2024]
Abstract
Human full-length (fl) αSyn fibrils, key neuropathological hallmarks of Parkinson's disease (PD), generate intense optical activity corresponding to the surface plasmon resonance of interacting gold nanorods. Herein, we analysed fibril-enriched protein extracts from mouse and human brain samples as well as from SK-N-SH cell lines with or without human fl and C-terminally truncated (Ctt) αSyn overexpression and exposed them to αSyn monomers, recombinant fl αSyn fibrils or Ctt αSyn fibrils. In vitro-generated human recombinant fl and Ctt αSyn fibrils and fibrils purified from SK-N-SH cells with fl or Ctt αSyn overexpression were also analysed using transmission electron microscopy (TEM) to gain insights into the nanorod-fibril complexes. We found that under the same experimental conditions, bisignate circular dichroism (CD) spectra of Ctt αSyn fibrils exhibited a blue-wavelength shift compared to that of fl αSyn fibrils. TEM results supported that this could be attributed to the different properties of nanorods. In our experimental conditions, fibril-enriched PD brain extract broadened the longitudinal surface plasmonic band with a bisignate CD couplet centred corresponding to the absorption band maximum. Plasmonic CD (PCD) couplets of in vivo- and in vitro-generated fibrils displayed sign reversal, suggesting their opposite handedness. Moreover, the incubation of in vitro-generated human recombinant fl αSyn fibrils in mouse brain extracts from αSyn null mice resulted in PCD couplet inversion, indicating that the biological environment may shape the handedness of αSyn fibrils. These findings support that nanorod-based PCD can provide useful information on the composition and features of αSyn fibrils from biological materials.
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Affiliation(s)
- Francesca Longhena
- Department of molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
- Department of Clinical Neurosciences-Clifford Allbutt Building, University of Cambridge, Hills Road CB2 0AH, Cambridge, UK
| | - Rihab Boujebene
- Department of molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| | - Viviana Brembati
- Department of molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| | - Michele Sandre
- Department of Biology, University of Padova, Via Ugo Bassi 58b, 35121 Padua, Italy
| | - Luigi Bubacco
- Department of Biology, University of Padova, Via Ugo Bassi 58b, 35121 Padua, Italy
| | - Sergio Abbate
- Department of molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
- Istituto Nazionale di Ottica, INO-CNR, Research Unit of Brescia, c/o CSMT, Via Branze 35, 25123 Brescia, Italy
| | - Giovanna Longhi
- Department of molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
- Istituto Nazionale di Ottica, INO-CNR, Research Unit of Brescia, c/o CSMT, Via Branze 35, 25123 Brescia, Italy
| | - Arianna Bellucci
- Department of molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
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Sato H, Inoué S, Yoshida J, Kawamura I, Koshoubu J, Yamagishi A. Microscopic vibrational circular dichroism on the forewings of a European hornet: heterogenous sequences of protein domains with different secondary structures. Phys Chem Chem Phys 2024; 26:17918-17922. [PMID: 38888259 DOI: 10.1039/d4cp01827c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
We developed a microscopic scanning for vibrational circular dichroism (VCD) spectroscopy in which a quantum cascade laser is equipped with a highly focused infrared light source to attain a spatial resolution of 100 μm. This system was applied to the forewing of a European hornet to reveal how the protein domains are organised. Two-dimensional patterns were obtained from the VCD signals with steps of 100 μm. We scanned the 1500-1740 cm-1 wavenumber range, which covers amide I and II absorptions. Zone sequenced α-helical and β-sheet domains within an area of 200 μm2 in membranes close to where two veins cross. The sign of the VCD signal at 1650 cm-1 changed from positive to negative when probed along the zone axis, intermediated by the absence of VCD activity. The significance of this zone is discussed from the viewpoint of the mechanical properties required for flying motion. These features are unattainable using conventional FTIR (Fourier transform infrared) or FT-VCD methods with a spatial resolution of ∼10 mm2.
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Affiliation(s)
- Hisako Sato
- Faculty of Science, Ehime University, 1 2-5, Bunkyo-cho, Matsuyama, 790-8577, Japan.
| | - Sayako Inoué
- Geodynamics Research Center, Ehime University, Matsuyama 790-8577, Japan
| | - Jun Yoshida
- Department of Chemistry, College of Humanities & Sciences, Nihon University, Setagaya-ku, Tokyo 156-8550, Japan
| | - Izuru Kawamura
- Graduate School of Engineering Science, Yokohama National University Yokohama, 240-8501, Japan
| | - Jun Koshoubu
- JASCO Corporation, Ishikawa 2967-5, Hachioji Tokyo, 192-8537, Japan
| | - Akihiko Yamagishi
- Faculty of Medicine, Toho University, 2 5-21-16 Oomori-nishi, Ota-ku, Tokyo, 143-8540, Japan
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Spasovová M, Kapitán J, Jílek Š, Siddhique Para Kkadan M, Klener J, Scott Lynn N, Kopecký V, Baumruk V, Profant V. Probing solution conformations of l-DOPA: Integration of experiment and simulation via vibrational optical activity. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 313:124119. [PMID: 38452461 DOI: 10.1016/j.saa.2024.124119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 02/24/2024] [Accepted: 03/03/2024] [Indexed: 03/09/2024]
Abstract
l-DOPA plays a critical role as a precursor to dopamine and is a standard treatment for Parkinson's disease. Recent research has highlighted the potential therapeutic advantages of deuterated l-DOPA analogs having a longer biological half-life. For their spectroscopic characterization, the in-detail characterization of l-DOPA itself is necessary. This article presents a thorough examination of the vibrational spectra of l-DOPA, with a particular emphasis on chirally sensitive VOA techniques. We successfully obtained high-quality Raman and ROA spectra of l-DOPA in its cationic form, under low pH conditions, and at a high concentration of 100 mg/ml. These spectra cover a broad spectral range, allowing for precise comparisons with theoretical simulations. We also obtained IR and VCD spectra, but they faced limitations due to the narrow accessible spectral region. Exploration of l-DOPA's conformational landscape revealed its intrinsic flexibility, with multiple coexisting conformations. To characterize these conformations, we employed two methods: one involved potential energy surface scans with implicit solvation, and the other utilized molecular dynamics simulations with explicit solvation. Comparing ROA spectra from different conformer groups and applying spectral decomposition proved crucial in determining the correct conformer ratios. The use of explicit solvation significantly improved the quality of the final simulated spectral profiles. The accurate determination of conformer ratios, rather than solely relying on the number of averaged spectra, played a crucial role in simulation accuracy. In conclusion, our study offers valuable insights into the structure and conformational behavior of l-DOPA and represents a valuable resource for subsequent spectroscopic studies of its deuterated analogs.
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Affiliation(s)
- Monika Spasovová
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic; FZU - Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 00 Prague 8, Czech Republic
| | - Josef Kapitán
- Department of Optics, Faculty of Sciences, Palacký University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - Štěpán Jílek
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - Mohammed Siddhique Para Kkadan
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic; Institute of Organic Chemistry and Biochemistry AS CR v.v.i., Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic
| | - Jakub Klener
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - Nicolas Scott Lynn
- FZU - Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 00 Prague 8, Czech Republic
| | - Vladimír Kopecký
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - Vladimír Baumruk
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - Václav Profant
- Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic.
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Sato H, Koshoubu J, Inoué S, Kawamura I, Yamagishi A. Multidimensional vibrational circular dichroism for insect wings: Comparison of species. Chirality 2024; 36:e23655. [PMID: 38419363 DOI: 10.1002/chir.23655] [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: 12/05/2023] [Revised: 01/16/2024] [Accepted: 02/02/2024] [Indexed: 03/02/2024]
Abstract
This study reports the microscopic measurements of vibrational circular dichroism (VCD) on four different insect wings using a quantum cascade laser VCD system equipped with microscopic scanning capabilities (named multi-dimensional VCD [MultiD-VCD]). Wing samples, including (i) beetle, Anomala albopilosa (female), (ii) European hornet, Verspa crabro flavofasciata Cameron, 1903 (female), (iii) tiny dragonfly, Nannophya pygmae Rambur, 1842 (male), and (iv) dragonfly, Symetrum gracile Oguma, 1915 (male), were used in this study. Two-dimensional patterns of VCD signals (~10 mm × 10 mm) were obtained at a spatial resolution of 100 μm. Measurements covered the absorption peaks assigned to amides I and II in the range of 1500-1740 cm-1 . The measurements were based on the enhancement of VCD signals for the stereoregular linkage of peptide groups. The patterns were remarkably dependent on the species. In samples (i) and (ii), the wings comprised segregated domains of protein aggregates of different secondary structures. The size of each microdomain was approximately 100 μm. In contrast, no clear VCD spectra were detected in samples (iii) and (iv). One possible reason was that the chain of stereoregular polypeptides was too short to achieve VCD enhancement in samples (iii) and (iv). Notably, the unique features were only observed in the VCD spectra because the IR spectra were nearly the same among the species. The VCD results hinted at the connection of protein microscopic structures with the wing flapping mechanisms of each species.
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Affiliation(s)
- Hisako Sato
- Faculty of Science, Ehime University, Matsuyama, Japan
| | | | - Sayako Inoué
- Geodynamics Research Center, Ehime University, Matsuyama, Japan
| | - Izuru Kawamura
- Graduate School of Engineering Science, Yokohama National University, Yokohama, Japan
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Schrenková V, Para Kkadan MS, Kessler J, Kapitán J, Bouř P. Molecular dynamics and Raman optical activity spectra reveal nucleotide conformation ratios in solution. Phys Chem Chem Phys 2023; 25:8198-8208. [PMID: 36880812 DOI: 10.1039/d2cp05756e] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Nucleotide conformational flexibility affects their biological functions. Although the spectroscopy of Raman optical activity (ROA) is well suited to structural analyses in aqueous solutions, the link between the spectral shape and the nucleotide geometry is not fully understood. We recorded the Raman and ROA spectra of model nucleotides (rAMP, rGMP, rCMP, and dTMP) and interpreted them on the basis of molecular dynamics (MD) combined with density functional theory (DFT). The relation between the sugar puckering, base conformation and spectral intensities is discussed. Hydrogen bonds between the sugar's C3' hydroxyl and the phosphate groups were found to be important for the sugar puckering. The simulated spectra correlated well with the experimental data and provided an understanding of the dependence of the spectral shapes on conformational dynamics. Most of the strongest spectral bands could be assigned to vibrational molecular motions. Decomposition of the experimental spectra into calculated subspectra based on arbitrary maps of free energies provided experimental conformer populations, which could be used to verify and improve the MD predictions. The analyses indicate some flaws of common MD force fields, such as being unable to describe the fine conformer distribution. Also the accuracy of conformer populations obtained from the spectroscopic data depends on the simulations, improvement of which is desirable for gaining a more detailed insight in the future. Improvement of the spectroscopic and computational methodology for nucleotides also provides opportunities for its application to larger nucleic acids.
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Affiliation(s)
- Věra Schrenková
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610 Prague, Czech Republic. .,Department of Analytical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic
| | - Mohammed Siddhique Para Kkadan
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610 Prague, Czech Republic. .,Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16, Prague, Czech Republic
| | - Jiří Kessler
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610 Prague, Czech Republic.
| | - Josef Kapitán
- Department of Optics, Palacký University Olomouc, 17. listopadu 12, 77146, Olomouc, Czech Republic
| | - Petr Bouř
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610 Prague, Czech Republic. .,Department of Analytical Chemistry, University of Chemistry and Technology, Technická 5, 16628 Prague, Czech Republic
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Aerts R, Bogaerts J, Herrebout W, Johannessen C. Insights in the vibrational optical activity spectra of the antibiotic vancomycin in DMSO. Phys Chem Chem Phys 2022; 24:9619-9625. [PMID: 35403645 DOI: 10.1039/d2cp00746k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Vibrational circular dichroism (VCD) and Raman optical activity (ROA) are two spectroscopic techniques that are sensitive towards the conformational behaviour of molecules, and are often complementary herein. In this work we pursue the determination of the conformational ensemble of the antibiotic glycopeptide vancomycin in DMSO through comparison of experimental and computational spectra, both for VCD and ROA. ROA is found to be highly suitable for the task, identifying an ensemble that strongly resembles the NMR conformation. In the case of VCD, however, a too high sensitivity of the intensities with respect to minor conformational changes hampers a reliable conformational analysis. Whence attempting to improve the match between the VCD experiment and calculations by any means - e.g., by inducing minor conformational changes or including solvent effects in the calculations - we show that there is the risk of going down the rabbit hole. In conclusion, this work contributes to the broader understanding of where, when and how VCD and ROA can be deployed as techniques for conformational analysis.
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Affiliation(s)
- Roy Aerts
- Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
| | - Jonathan Bogaerts
- Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
| | - Wouter Herrebout
- Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
| | - Christian Johannessen
- Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
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Yamamoto S, Ishiro S, Kessler J, Bouř P. Intense chiral signal from α-helical poly-L-alanine observed in low-frequency Raman optical activity. Phys Chem Chem Phys 2021; 23:26501-26509. [PMID: 34806737 DOI: 10.1039/d1cp04401j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Raman optical activity (ROA) spectral features reliably indicate the structure of peptides and proteins, but the signal is often weak. However, we observed significantly enhanced low-frequency bands for α-helical poly-L-alanine (PLA) in solution. The biggest ROA signal at ∼100 cm-1 is about 10 times stronger than higher-frequency bands described previously, which facilitates the detection. The low-frequency bands of PLA were compared to those of α-helical proteins. For PLA, density functional simulations well reproduced the experimental spectra and revealed that about 12 alanine residues within two turns of the α-helix generate the strong ROA band. Averaging based on molecular dynamics (MD) provided an even more realistic spectrum compared to the static model. The low-frequency bands could be largely related to a collective motion of the α-helical backbone, partially modulated by the solvent. Helical and intermolecular vibrational coordinates have been introduced and the helical unwinding modes were assigned to the strongest ROA signal at 101-128 cm-1. Further analysis indicated that the helically arranged amide and methyl groups are important for the strong chiral signal of PLA, while the local chiral centers CαH contribute in a minor way only. The strong low-frequency ROA can thus provide precious information about the motions of the peptide backbone and facilitate future protein studies.
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Affiliation(s)
- Shigeki Yamamoto
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka 560-0043, Japan.
| | - Shota Ishiro
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka 560-0043, Japan.
| | - Jiří Kessler
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610 Prague, Czech Republic.
| | - Petr Bouř
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, Flemingovo náměstí 2, 16610 Prague, Czech Republic.
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Bogaerts J, Aerts R, Vermeyen T, Johannessen C, Herrebout W, Batista JM. Tackling Stereochemistry in Drug Molecules with Vibrational Optical Activity. Pharmaceuticals (Basel) 2021; 14:877. [PMID: 34577577 PMCID: PMC8468215 DOI: 10.3390/ph14090877] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 12/29/2022] Open
Abstract
Chirality plays a crucial role in drug discovery and development. As a result, a significant number of commercially available drugs are structurally dissymmetric and enantiomerically pure. The determination of the exact 3D structure of drug candidates is, consequently, of paramount importance for the pharmaceutical industry in different stages of the discovery pipeline. Traditionally the assignment of the absolute configuration of druggable molecules has been carried out by means of X-ray crystallography. Nevertheless, not all molecules are suitable for single-crystal growing. Additionally, valuable information about the conformational dynamics of drug candidates is lost in the solid state. As an alternative, vibrational optical activity (VOA) methods have emerged as powerful tools to assess the stereochemistry of drug molecules directly in solution. These methods include vibrational circular dichroism (VCD) and Raman optical activity (ROA). Despite their potential, VCD and ROA are still unheard of to many organic and medicinal chemists. Therefore, the present review aims at highlighting the recent use of VOA methods for the assignment of the absolute configuration of chiral small-molecule drugs, as well as for the structural analysis of biologics of pharmaceutical interest. A brief introduction on VCD and ROA theory and the best experimental practices for using these methods will be provided along with selected representative examples over the last five years. As VCD and ROA are commonly used in combination with quantum calculations, some guidelines will also be presented for the reliable simulation of chiroptical spectra. Special attention will be paid to the complementarity of VCD and ROA to unambiguously assess the stereochemical properties of pharmaceuticals.
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Affiliation(s)
- Jonathan Bogaerts
- Department of Chemistry, University of Antwerp, 2020 Antwerp, Belgium; (J.B.); (R.A.); (T.V.); (C.J.); (W.H.)
| | - Roy Aerts
- Department of Chemistry, University of Antwerp, 2020 Antwerp, Belgium; (J.B.); (R.A.); (T.V.); (C.J.); (W.H.)
| | - Tom Vermeyen
- Department of Chemistry, University of Antwerp, 2020 Antwerp, Belgium; (J.B.); (R.A.); (T.V.); (C.J.); (W.H.)
- Department of Chemistry, Ghent University, 9000 Ghent, Belgium
| | - Christian Johannessen
- Department of Chemistry, University of Antwerp, 2020 Antwerp, Belgium; (J.B.); (R.A.); (T.V.); (C.J.); (W.H.)
| | - Wouter Herrebout
- Department of Chemistry, University of Antwerp, 2020 Antwerp, Belgium; (J.B.); (R.A.); (T.V.); (C.J.); (W.H.)
| | - Joao M. Batista
- Institute of Science and Technology, Federal University of Sao Paulo, Sao Jose dos Campos 12231-280, SP, Brazil
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Sato H, Yamagishi A, Shimizu M, Watanabe K, Koshoubu J, Yoshida J, Kawamura I. Mapping of Supramolecular Chirality in Insect Wings by Microscopic Vibrational Circular Dichroism Spectroscopy: Heterogeneity in Protein Distribution. J Phys Chem Lett 2021; 12:7733-7737. [PMID: 34355918 DOI: 10.1021/acs.jpclett.1c01949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The supramolecular chirality of the hindwing of Anomala albopilosa (male) was investigated using a microscopic vibrational circular dichroism (VCD) system, denoted as MultiD-VCD. The source of intense infrared (IR) light for the system was a quantum cascade laser. Two-dimensional maps of IR and VCD spectra were taken by scanning the surface area (ca. 2 mm × 2 mm) of the insect hindwing tissue. The spectra ranged from 1500 to 1700 cm-1, and the maps have a spatial resolution of 100 μm. The distribution of proteins, including their supramolecular structures, was analyzed from the location-dependent spectral shape of the VCD bands assigned to amides I and II. The results revealed that the hindwing consists of segregated domains of proteins with different secondary structures: an α-helix (in one part of the membrane), a hybrid of α-helix and β-sheet (in another part of the membrane), and a coil (in a vein).
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Affiliation(s)
- Hisako Sato
- Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-chou, Matsuyama, Ehime 790-8577, Japan
| | - Akihiko Yamagishi
- Department of Medicine, Faculty of Medicine, Toho University, Ota-ku 143-8540, Japan
| | - Masaru Shimizu
- JASCO Corporation, Ishikawa 2967-5, Hachioji, Tokyo 192-8537, Japan
| | - Keisuke Watanabe
- JASCO Corporation, Ishikawa 2967-5, Hachioji, Tokyo 192-8537, Japan
| | - Jun Koshoubu
- JASCO Corporation, Ishikawa 2967-5, Hachioji, Tokyo 192-8537, Japan
| | - Jun Yoshida
- Department of Chemistry, College of Humanities & Sciences, Nihon University, 3-25-40 Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan
| | - Izuru Kawamura
- Graduate School of Engineering Science, Yokohama National University, Hodogaya-ku, Yokohama 240-8501, Japan
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