1
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Cecchet F. Light on the interactions between nanoparticles and lipid membranes by interface-sensitive vibrational spectroscopy. Colloids Surf B Biointerfaces 2024; 241:114013. [PMID: 38865867 DOI: 10.1016/j.colsurfb.2024.114013] [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: 02/27/2024] [Revised: 05/10/2024] [Accepted: 06/03/2024] [Indexed: 06/14/2024]
Abstract
Nanoparticles are produced in natural phenomena or synthesized artificially for technological applications. Their frequent contact with humans has been judged potentially harmful for health, and numerous studies are ongoing to understand the mechanisms of the toxicity of nanoparticles. At the macroscopic level, the toxicity can be established in vitro or in vivo by measuring the survival of cells. At the sub-microscopic level, scientists want to unveil the molecular mechanisms of the first interactions of nanoparticles with cells via the cell membrane, before the toxicity cascades within the whole cell. Unveiling a molecular understanding of the nanoparticle-membrane interface is a tricky challenge, because of the chemical complexity of this system and its nanosized dimensions buried within bulk macroscopic environments. In this review, we highlight how, in the last 10 years, second-order nonlinear optical (NLO) spectroscopy, and specifically vibrational sum frequency generation (SFG), has provided a new understanding of the structural, physicochemical, and dynamic properties of these biological interfaces, with molecular sensitivity. We will show how the intrinsic interfacial sensitivity of second-order NLO and the chemical information of vibrational SFG spectroscopy have revealed new knowledge of the molecular mechanisms that drive nanoparticles to interact with cell membranes, from both sides, the nanoparticles and the membrane properties.
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Affiliation(s)
- Francesca Cecchet
- Laboratory of Lasers and Spectroscopies (LLS), Namur Institute of Structured Matter (NISM) and NAmur Institute for Life Sciences (NARILIS), University of Namur (UNamur), Belgium.
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2
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Strunge K, Burgin T, Golbek TW, Roeters SJ, Pfaendtner J, Weidner T. Umbrella-like Helical Structure of α-Synuclein at the Air-Water Interface Observed with Experimental and Theoretical Sum Frequency Generation Spectroscopy. J Phys Chem Lett 2023; 14:11030-11035. [PMID: 38047768 DOI: 10.1021/acs.jpclett.3c02543] [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: 12/05/2023]
Abstract
The misfolding of α-synuclein (αS) into amyloid aggregates is catalyzed by hydrophobic surfaces and associated with severe brain disorders, such as Parkinson's disease. Despite the important role of interfaces, the three-dimensional structure of αS at the interfaces is still not clear. We report interface-specific sum frequency generation (SFG) experiments of monomeric αS binding to the air-water interface, a model system for the important hydrophobic surfaces. We combine the SFG spectra with calculations of theoretical spectra based on molecular dynamics simulations to show that αS, which is an intrinsically disordered protein in solution, folds into a defined, mostly helical secondary structure at the air-water interface. The binding pose resembles an umbrella shape, where the C-terminus protrudes into the water phase, while the N-terminus and the NAC region span the canopy at the interface. In this binding pose, αS is prone to aggregate, which could explain the catalytic effect of hydrophobic interfaces and air bubbles on αS fibrillation.
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Affiliation(s)
- Kris Strunge
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Tucker Burgin
- Department of Chemical Engineering, University of Washington, Benson Hall 1750, Seattle, Washington 98195-1750, United States
| | - Thaddeus W Golbek
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Steven J Roeters
- Department of Anatomy and Neurosciences, Vrije University, Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Jim Pfaendtner
- Department of Chemical Engineering, University of Washington, Benson Hall 1750, Seattle, Washington 98195-1750, United States
| | - Tobias Weidner
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
- Department of Chemical Engineering, University of Washington, Benson Hall 1750, Seattle, Washington 98195-1750, United States
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3
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Konstantinovsky D, Yan ECY, Hammes-Schiffer S. Characterizing Interfaces by Voronoi Tessellation. J Phys Chem Lett 2023; 14:5260-5266. [PMID: 37265175 PMCID: PMC10344600 DOI: 10.1021/acs.jpclett.3c01159] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The chemistry of interfaces differs markedly from that of the bulk. Calculation of interfacial properties depends strongly on the definition of the interface, which can lead to ambiguous results that vary between studies. There is a need for a method that can explicitly define the interfaces and boundaries in molecular systems. Voronoi tessellation offers an attractive solution to this problem through its ability to determine neighbors among specified groups of atoms. Here we discuss three cases where Voronoi tessellation combined with modeling of vibrational sum frequency generation (SFG) spectroscopy yields relevant insights: the breakdown of the air-water interface into clear and intuitive molecular layers, the study of the hydration shell in biological systems, and the acceleration of difficult spectral calculations where intermolecular vibrational couplings dominate. The utility of Voronoi tessellation has broad applications that extend beyond any single type of spectroscopy or system.
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Affiliation(s)
- Daniel Konstantinovsky
- Department of Chemistry, Yale University, New Haven, CT, USA 06511
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA 06511
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, New Haven, CT, USA 06511
| | - Sharon Hammes-Schiffer
- Department of Chemistry, Yale University, New Haven, CT, USA 06511
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA 06511
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4
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Konstantinovsky D, Perets EA, Santiago T, Olesen K, Wang Z, Soudackov AV, Yan ECY, Hammes-Schiffer S. Design of an Electrostatic Frequency Map for the NH Stretch of the Protein Backbone and Application to Chiral Sum Frequency Generation Spectroscopy. J Phys Chem B 2023; 127:2418-2429. [PMID: 36916645 PMCID: PMC10409516 DOI: 10.1021/acs.jpcb.3c00217] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Abstract
We develop an electrostatic map for the vibrational NH stretch (amide A) of the protein backbone with a focus on vibrational chiral sum frequency generation spectroscopy (chiral SFG). Chiral SFG has been used to characterize protein secondary structure at interfaces using the NH stretch and to investigate chiral water superstructures around proteins using the OH stretch. Interpretation of spectra has been complicated because the NH stretch and OH stretch overlap spectrally. Although an electrostatic map for water OH developed by Skinner and co-workers was used previously to calculate the chiral SFG response of water structures around proteins, a map for protein NH that is directly responsive to biological complexity has yet to be developed. Here, we develop such a map, linking the local electric field to vibrational frequencies and transition dipoles. We apply the map to two protein systems and achieve much better agreement with experiment than was possible in our previous studies. We show that couplings between NH and OH vibrations are crucial to the line shape, which informs the interpretation of chiral SFG spectra, and that the chiral NH stretch response is sensitive to small differences in structure. This work increases the utility of the NH stretch in biomolecular spectroscopy.
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Affiliation(s)
- Daniel Konstantinovsky
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, United States
| | - Ethan A. Perets
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
- Current Address: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Ty Santiago
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
| | - Kristian Olesen
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
| | - Zhijie Wang
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
| | | | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
| | - Sharon Hammes-Schiffer
- Department of Chemistry, Yale University, New Haven, CT 06520, United States
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, United States
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5
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Li B, Ma Y, Han X, Hu P, Lu X. Enhanced Sum Frequency Generation for Monolayers on Au Relative to Silica: Local Field Factors and SPR Effect. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:659-667. [PMID: 36580605 DOI: 10.1021/acs.langmuir.2c03016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Using metals as signal magnified substrates, surface plasmon-enhanced sum frequency generation (SFG) vibrational spectroscopy is a promising technique to probe weak molecular-level signals at surfaces and interfaces. In this study, the vibrational signals of the n-alkane monolayer on the gold (Au) and silica substrates are investigated using the broadband femtosecond SFG. The enhancement factors are discovered to be up to ∼1076 and ∼31 for the methyl symmetric and asymmetric stretching (ss and as) modes of the monolayer, respectively. By systematically analyzing the second-order nonlinear susceptibility tensor components (χijks), the Fresnel coefficients (Fijks), and the surface plasmon resonance (SPR) effect, we find that the interplay between Fijk and χijk terms and the SPR effect dominate the SFG signal enhancement. Our study reveals that the relative contributions of different influencing factors (i.e., Fresnel coefficients and SPR) to the SFG signal enhancement provide an approach to interpreting enhanced SFG vibrational signals detected from probe molecules on distinct substrates and may finally guide the design of the experimental methodology to improve the detection sensitivity and signal-to-noise ratio.
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Affiliation(s)
- Bolin Li
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory (HMFL), Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences, Hefei, Anhui230031, P. R. China
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing210096, China
| | - Yonghao Ma
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing210096, China
| | - Xiaofeng Han
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing210096, China
| | - Pengcheng Hu
- School of Medical Imaging, Xuzhou Medical College, Xuzhou, Jiangsu221004, China
| | - Xiaolin Lu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing210096, China
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6
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Rimoli CV, de Oliveira Pedro R, Miranda PB. Interaction mechanism of chitosan oligomers in pure water with cell membrane models studied by SFG vibrational spectroscopy. Colloids Surf B Biointerfaces 2022; 219:112782. [PMID: 36063719 DOI: 10.1016/j.colsurfb.2022.112782] [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: 05/18/2022] [Revised: 08/10/2022] [Accepted: 08/17/2022] [Indexed: 11/20/2022]
Abstract
Chitosan is a versatile and biocompatible cationic antimicrobial polymer obtained from sustainable sources that is effective against a wide range of microorganisms. Although it is soluble only at low pH, chitosan oligomers (ChitO) are soluble in pure water and thus more appropriate for antibacterial applications. Although there is a vast literature on chitosan's antimicrobial activity, the molecular details of its interaction with biomembranes remain unclear. Here we investigate these molecular interactions by resorting to phospholipid Langmuir films (zwitterionic DPPC and anionic DPPG) as simplified membrane models (for mammalian and bacterial membranes, respectively), and using SFG vibrational spectroscopy to probe lipid tail conformation, headgroup dynamics and interfacial water orientation. For comparison, we also investigate the interactions of another simple cationic antimicrobial polyelectrolyte, poly(allylamine) hydrochloride - PAH. By forming the lipid films over the polyelectrolyte solutions, we found that both have only a very small interaction with DPPC, but PAH adsorption is able to invert the interfacial water orientation (membrane potential). This might explain why ChitO is compatible with mammalian cells, while PAH is toxic. In contrast, their interaction with DPPG films is much stronger, even more so for ChitO, with both insertion within the lipid film and interaction with the oppositely charged headgroups. Again, PAH adsorption inverts the membrane potential, while ChitO does not. Finally, ChitO interaction with DPPG is weaker if the antimicrobial is injected underneath a pre-assembled Langmuir film, and its interaction mode depends on the time interval between end of film compression and ChitO injection. These differences between ChitO and PAH effects on the model membranes highlight the importance of molecular structure and intermolecular interactions for their bioactivity, and therefore this study may provide insights for the rational design of more effective antimicrobial molecules.
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Affiliation(s)
- Caio Vaz Rimoli
- Sao Carlos Physics Institute, University of Sao Paulo, CP 369, Sao Carlos CEP 13560-970, SP, Brazil; Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, College de France, 24 Rue Lhomond, F-75005 Paris, France
| | - Rafael de Oliveira Pedro
- Sao Carlos Physics Institute, University of Sao Paulo, CP 369, Sao Carlos CEP 13560-970, SP, Brazil; Department of exact and earth sciences, Minas Gerais State University (UEMG), Ituiutaba CEP 38302-192, MG, Brazil
| | - Paulo B Miranda
- Sao Carlos Physics Institute, University of Sao Paulo, CP 369, Sao Carlos CEP 13560-970, SP, Brazil.
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7
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Konstantinovsky D, Perets EA, Santiago T, Velarde L, Hammes-Schiffer S, Yan ECY. Detecting the First Hydration Shell Structure around Biomolecules at Interfaces. ACS CENTRAL SCIENCE 2022; 8:1404-1414. [PMID: 36313165 PMCID: PMC9615115 DOI: 10.1021/acscentsci.2c00702] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Indexed: 05/15/2023]
Abstract
Understanding the role of water in biological processes remains a central challenge in the life sciences. Water structures in hydration shells of biomolecules are difficult to study in situ due to overwhelming background from aqueous environments. Biological interfaces introduce additional complexity because biomolecular hydration differs at interfaces compared to bulk solution. Here, we perform experimental and computational studies of chiral sum frequency generation (chiral SFG) spectroscopy to probe chirality transfer from a protein to the surrounding water molecules. This work reveals that chiral SFG probes the first hydration shell around the protein almost exclusively. We explain the selectivity to the first hydration shell in terms of the asymmetry induced by the protein structure and specific protein-water hydrogen-bonding interactions. This work establishes chiral SFG as a powerful technique for studying hydration shell structures around biomolecules at interfaces, presenting new possibilities to address grand research challenges in biology, including the molecular origins of life.
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Affiliation(s)
- Daniel Konstantinovsky
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520, United States
- Department
of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Ethan A. Perets
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Ty Santiago
- Department
of Chemistry, University at Buffalo, Buffalo, New York 14260, United States
| | - Luis Velarde
- Department
of Chemistry, University at Buffalo, Buffalo, New York 14260, United States
| | | | - Elsa C. Y. Yan
- Department
of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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8
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Tutorial on the instrumentation of sum frequency generation vibrational spectroscopy: Using a Ti:sapphire based system as an example. Biointerphases 2022; 17:051201. [PMID: 36070973 DOI: 10.1116/6.0002007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Sum frequency generation vibrational spectroscopy (SFG-VS) is an intrinsically surface-selective vibrational spectroscopic technique based on the second-order nonlinear optical process. Since its birth in the 1980s, SFG-VS has been used to solve interfacial structure and dynamics in a variety of research fields including chemistry, physics, materials sciences, biological sciences, environmental sciences, etc. Better understanding of SFG-VS instrumentation is no doubt an essential step to master this sophisticated technique. To address this need, here we will present a Tutorial with respect to the classification, setup layout, construction, operation, and data processing about SFG-VS. We will focus on the steady state Ti:sapphire based broad bandwidth SFG-VS system and use it as an example. We hope this Tutorial is beneficial for newcomers to the SFG-VS field and for people who are interested in using SFG-VS technique in their research.
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9
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Perets EA, Olesen KB, Yan ECY. Chiral Sum Frequency Generation Spectroscopy Detects Double-Helix DNA at Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:5765-5778. [PMID: 35482888 DOI: 10.1021/acs.langmuir.2c00365] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Many DNA-based technologies involve the immobilization of DNA and therefore require a fundamental understanding of the DNA structure-function relationship at interfaces. We present three immobilization methods compatible with chiral sum frequency generation (SFG) spectroscopy at interfaces. They are the "anchor" method for covalently attaching DNA on a glass surface, the "island" method for dropcasting DNA on solid substrates, and the "buoy" method using a hydrocarbon moiety for localizing DNA at the air-water interface. Although SFG was previously used to probe DNA, the chiral and achiral SFG responses of single-stranded and double-stranded DNA have not been compared systemically. Using the three immobilization methods, we obtain the achiral and chiral C-H stretching spectra. The results introduce four potential applications of chiral SFG. First, chiral SFG gives null response from single-stranded DNA but prominent signals from double-stranded DNA, providing a simple binary readout for label-free detection of DNA hybridization. Second, with heterodyne detection, chiral SFG gives an opposite-signed spectral response useful for distinguishing native (D-) right-handed double helix from non-native (L-) left-handed double helix. Third, chiral SFG captures the aromatic C-H stretching modes of nucleobases that emerge upon hybridization, revealing the power of chiral SFG to probe highly localized molecular structures within DNA. Finally, chiral SFG is sensitive to macroscopic chirality but not local chiral centers and thus can detect not only canonical antiparallel double helix but also other DNA secondary structures, such as a poly-adenine parallel double helix. Our work benchmarks the SFG responses of DNA immobilized by the three distinct methods, building a basis for new chiral SFG applications to solve fundamental and biotechnological problems.
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Affiliation(s)
- Ethan A Perets
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Kristian B Olesen
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Elsa C Y Yan
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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10
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Mirror-image antiparallel β-sheets organize water molecules into superstructures of opposite chirality. Proc Natl Acad Sci U S A 2020; 117:32902-32909. [PMID: 33318168 DOI: 10.1073/pnas.2015567117] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Biomolecular hydration is fundamental to biological functions. Using phase-resolved chiral sum-frequency generation spectroscopy (SFG), we probe molecular architectures and interactions of water molecules around a self-assembling antiparallel β-sheet protein. We find that the phase of the chiroptical response from the O-H stretching vibrational modes of water flips with the absolute chirality of the (l-) or (d-) antiparallel β-sheet. Therefore, we can conclude that the (d-) antiparallel β-sheet organizes water solvent into a chiral supermolecular structure with opposite handedness relative to that of the (l-) antiparallel β-sheet. We use molecular dynamics to characterize the chiral water superstructure at atomic resolution. The results show that the macroscopic chirality of antiparallel β-sheets breaks the symmetry of assemblies of surrounding water molecules. We also calculate the chiral SFG response of water surrounding (l-) and (d-) LK7β to confirm the presence of chiral water structures. Our results offer a different perspective as well as introduce experimental and computational methodologies for elucidating hydration of biomacromolecules. The findings imply potentially important but largely unexplored roles of water solvent in chiral selectivity of biomolecular interactions and the molecular origins of homochirality in the biological world.
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11
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Hao H, Xie Q, Ai J, Wang Y, Bian H. Specific counter-cation effect on the molecular orientation of thiocyanate anions at the aqueous solution interface. Phys Chem Chem Phys 2020; 22:10106-10115. [PMID: 32342973 DOI: 10.1039/d0cp00974a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Understanding the interfacial structure of aqueous electrolyte solutions is important and relevant to a wide range of systems, ranging from atmospheric aerosols to electrochemistry, and biological environments. Though significant efforts have been made to unravel the interfacial structure of water molecules, the structure and dynamics of ions at the interface have not yet been fully elucidated. Here, the interfacial structure of the aqueous solution was investigated directly by monitoring the thiocyanate (SCN-) anions using surface-specific sum frequency generation (SFG) vibrational spectroscopy. The molecular orientation of the SCN- anions and their adsorption behavior at the air/water interface were systematically determined by quantitative polarization analysis. The transition dipole of the CN stretching of the SCN- anion is oriented around 44° from the surface normal of the NaSCN aqueous solution surface and remained unchanged with the bulk concentration varying from 1 mol kg-1 to 13 mol kg-1. The free energy of adsorption of SCN- anions at the air/water interface was determined to be -1.53 ± 0.04 kcal mol-1. Furthermore, a new SFG peak positioned at 2080 cm-1 in the ppp polarization combination was observed at the air/15.0 mol kg-1 NaSCN aqueous solution interface for the first time. Concentration-dependent SFG analysis and density functional theory (DFT) calculation further revealed that the SCN- anions form an ion clustering structure at the air/water interface. The subtle and specific Na+ and K+ counter-cation effects on the interfacial structure of the SCN- anions at the aqueous solution interface were also observed, which showed that ion cooperativity plays an important role in affecting the interfacial structure of ions at the air/water interface. The results are expected to yield significant insights into the understanding of the structure of aqueous solution surfaces and the molecular level mechanism of the cationic Hofmeister effect.
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Affiliation(s)
- Hongxing Hao
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
| | - Qing Xie
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
| | - Jingwen Ai
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
| | - Yuan Wang
- Institute of Science and Technology, University of Sanya, Sanya, Hainan 572022, China
| | - Hongtao Bian
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
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12
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Hosseinpour S, Roeters SJ, Bonn M, Peukert W, Woutersen S, Weidner T. Structure and Dynamics of Interfacial Peptides and Proteins from Vibrational Sum-Frequency Generation Spectroscopy. Chem Rev 2020; 120:3420-3465. [DOI: 10.1021/acs.chemrev.9b00410] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Saman Hosseinpour
- Institute of Particle Technology (LFG), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | | | - Mischa Bonn
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Wolfgang Peukert
- Institute of Particle Technology (LFG), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Sander Woutersen
- Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, 1098 EP Amsterdam, The Netherlands
| | - Tobias Weidner
- Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
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13
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Perets EA, Videla PE, Yan ECY, Batista VS. Chiral Inversion of Amino Acids in Antiparallel β-Sheets at Interfaces Probed by Vibrational Sum Frequency Generation Spectroscopy. J Phys Chem B 2019; 123:5769-5781. [PMID: 31194546 PMCID: PMC9059514 DOI: 10.1021/acs.jpcb.9b04029] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A parallel study of protein variants with all (l-), all (d-), or mixed (l-)/(d-) amino acids can be used to assess how backbone architecture versus side chain identity determines protein structure. Here, we investigate the secondary structure and side chain orientation dynamics of the antiparallel β-sheet peptide LK7β (Ac-Leu-Lys-Leu-Lys-Leu-Lys-Leu-NH2) composed of all (l-), all (d-), or alternating (l-Leu)/(d-Lys) amino acids. Using interface-selective vibrational sum frequency generation spectroscopy (VSFG), we observe that the alternating (l-)/(d-) peptide lacks a resonant C-H stretching mode compared to the (l-) and (d-) variants and does not form antiparallel β-sheets. We rationalize our observations on the basis of density functional theory calculations and molecular dynamics (MD) simulations of LK7β at the air-water interface. Irrespective of the handedness of the amino acids, leucine side chains prefer to orient toward the hydrophobic air phase while lysine side chains prefer the hydrophilic water phase. These preferences dictate the backbone configuration of LK7β and thereby the folding of the peptide. Our MD simulations show that the preferred side chain orientations can force the backbone of a single strand of (l-) LK7β at the air-water interface to adopt β-sheet Ramachandran angles. However, denaturation of the β-sheets at pH = 2 results in a negligible chiral VSFG amide I response. The combined computational and experimental results lend critical support to the theory that a chiral VSFG response requires macroscopic chirality, such as in β-sheets. Our results can guide expectations about the VSFG optical responses of proteins and should improve understanding of how amino acid chirality modulates the structure and function of natural and de novo proteins at biological interfaces.
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Affiliation(s)
- Ethan A. Perets
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, CT 06520
| | - Pablo E. Videla
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, CT 06520
- Energy Sciences Institute, Yale University, 810 West Campus Drive, West Haven, CT 06516
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, CT 06520
| | - Victor S. Batista
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, CT 06520
- Energy Sciences Institute, Yale University, 810 West Campus Drive, West Haven, CT 06516
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14
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Perets EA, Yan ECY. Chiral Water Superstructures around Antiparallel β-Sheets Observed by Chiral Vibrational Sum Frequency Generation Spectroscopy. J Phys Chem Lett 2019; 10:3395-3401. [PMID: 31070921 PMCID: PMC9059516 DOI: 10.1021/acs.jpclett.9b00878] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Hydration modulates every aspect of protein structure and function. However, studying water structures in hydration shells remains challenging mostly due to overwhelming background from bulk water. We used vibrational sum frequency generation (SFG) spectroscopy to characterize hydrated films of an antiparallel β-sheet peptide (LK7β) adsorbed on glass slides. The hydrated films give chiral SFG response from water only when the peptide self-assembles into antiparallel β-sheets. Experiments of isotopic labeling, isotopic dilution of water, and H2O-D2O exchange kinetics corroborate the assignments of the chiral SFG response to water stretching modes. Because individual water molecules are achiral, the chiral SFG response indicates formation of chiral superstructures of water around the antiparallel β-sheet, implying that a protein secondary structure can imprint its chirality onto the surrounding water. This result demonstrates chiral SFG spectroscopy as a promising tool for probing water structures in protein hydration and addressing fundamental questions of protein structure-function.
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Affiliation(s)
- Ethan A. Perets
- Department of Chemistry, Yale University, New Haven, Connecticut 06520 United States
| | - E. Chui-Ying Yan
- Department of Chemistry, Yale University, New Haven, Connecticut 06520 United States
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15
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Heiner Z, Wang L, Petrov V, Mero M. Broadband vibrational sum-frequency generation spectrometer at 100 kHz in the 950-1750 cm -1 spectral range utilizing a LiGaS 2 optical parametric amplifier. OPTICS EXPRESS 2019; 27:15289-15297. [PMID: 31163726 DOI: 10.1364/oe.27.015289] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/08/2019] [Indexed: 06/09/2023]
Abstract
We present a 100 kHz broadband vibrational sum-frequency generation (VSFG) spectrometer operating in the 5.7-10.5 µm (950-1750 cm-1) wavelength range. The mid-infrared beam of the system is obtained from a collinear, type-I LiGaS2-crystal-based optical parametric amplifier seeded by a supercontinuum and pumped directly by 180 fs, ~32 µJ, 1.03 µm pulses from an Yb:KGd(WO4)2 laser system. Up to 0.5 µJ mid-infrared pulses with durations below 100 fs were obtained after dispersion compensation utilizing bulk materials. We demonstrate the utility of the spectrometer by recording high-resolution, low-noise vibrational spectra of Langmuir-Blodgett supported lipid monolayers on CaF2. The presented VSFG spectrometer scheme offers superior signal-to-noise ratios and constitutes a high-efficiency, low-cost, easy-to-use alternative to traditional schemes relying on optical parametric amplification followed by difference frequency generation.
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16
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High-resolution and high-repetition-rate vibrational sum-frequency generation spectroscopy of one- and two-component phosphatidylcholine monolayers. Anal Bioanal Chem 2019; 411:4861-4871. [DOI: 10.1007/s00216-019-01690-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 01/21/2019] [Accepted: 02/13/2019] [Indexed: 01/23/2023]
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17
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Pan X, Yang F, Chen S, Zhu X, Wang C. Cooperative Effects of Zwitterionic-Ionic Surfactant Mixtures on the Interfacial Water Structure Revealed by Sum Frequency Generation Vibrational Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:5273-5278. [PMID: 29672067 DOI: 10.1021/acs.langmuir.8b00178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cooperative effects of a series of equimolar binary zwitterionic-ionic surfactant mixtures on the interfacial water structure at the air-water interfaces have been studied by sum frequency generation vibrational spectroscopy (SFG-VS). For zwitterionic surfactant palmityl sulfobetaine (SNC16), anionic surfactant sodium hexadecyl sulfate (SHS), and cationic surfactant cetyltrimethylammonium bromide (CTAB) with the same length of alkyl chain, significantly enhanced ordering of interfacial water molecules was observed for the zwitterionic-anionic surfactant mixtures SNC16-SHS, indicating that SNC16 interacts more strongly with SHS than with CTAB because of the strong headgroup-headgroup electrostatic attraction for SNC16-SHS. Meanwhile, the SFG amplitude ratio of methyl and methylene symmetric stretching modes was used to verify the stronger interaction between SNC16 and SHS. The conformational order indicator increased from 0.64 for SNC16 to 7.17 for SNC16-SHS but only 0.94 for SNC16-CTAB. In addition, another anionic surfactant sodium dodecyl sulfate (SDS) was introduced to study the influence of chain-chain interaction. Decreased SFG amplitude of interfacial water molecules for SNC16-SDS was observed. Therefore, both the headgroup-headgroup electrostatic interaction and chain-chain van der Waals attractive interaction of the surfactants play an important role in enhancing the ordering of interfacial water molecules. The results provided experimental and theoretical bases for practical applications of the surfactants.
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Affiliation(s)
- Xuecong Pan
- Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics and Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments , Chinese Academy of Sciences , 40-1 South Beijing Road , Urumqi 830011 , Xinjiang , China
- Laboratory of Nanofiber Membrane Materials and Devices , Xinjiang University Institute of Science and Technology , 1 Xuefu Road , Akesu 843100 , Xinjiang , China
| | - Fangyuan Yang
- Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics and Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments , Chinese Academy of Sciences , 40-1 South Beijing Road , Urumqi 830011 , Xinjiang , China
| | - Shunli Chen
- Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics and Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments , Chinese Academy of Sciences , 40-1 South Beijing Road , Urumqi 830011 , Xinjiang , China
| | - Xuefeng Zhu
- Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics and Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments , Chinese Academy of Sciences , 40-1 South Beijing Road , Urumqi 830011 , Xinjiang , China
| | - Chuanyi Wang
- Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics and Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments , Chinese Academy of Sciences , 40-1 South Beijing Road , Urumqi 830011 , Xinjiang , China
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18
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Chowdhury AU, Liu F, Watson BR, Ashkar R, Katsaras J, Collier CP, Lutterman DA, Ma YZ, Calhoun TR, Doughty B. Flexible approach to vibrational sum-frequency generation using shaped near-infrared light. OPTICS LETTERS 2018; 43:2038-2041. [PMID: 29714740 PMCID: PMC6343496 DOI: 10.1364/ol.43.002038] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 03/03/2018] [Indexed: 05/28/2023]
Abstract
We describe a new approach that expands the utility of vibrational sum-frequency generation (vSFG) spectroscopy using shaped near-infrared (NIR) laser pulses. We demonstrate that arbitrary pulse shapes can be specified to match experimental requirements without the need for changes to the optical alignment. In this way, narrowband NIR pulses as long as 5.75 ps are readily generated, with a spectral resolution of about 2.5 cm-1, an improvement of approximately a factor of 3 compared to a typical vSFG system. Moreover, the utility of having complete control over the NIR pulse characteristics is demonstrated through nonresonant background suppression from a metallic substrate by generating an etalon waveform in the pulse shaper. The flexibility afforded by switching between arbitrary NIR waveforms at the sample position with the same instrument geometry expands the type of samples that can be studied without extensive modifications to existing apparatuses or large investments in specialty optics.
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Affiliation(s)
- Azhad U. Chowdhury
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831
| | - Fangjie Liu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831
| | - Brianna R. Watson
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996
| | - Rana Ashkar
- Department of Physics, Virginia Tech, Blacksburg, VA 24061
| | - John Katsaras
- Large Scale Structures Group, Neutron Sciences Directorate and Shull Wollan Center: A Joint Institute for Neutron Science, Oak Ridge National Laboratory, Oak Ridge, TN 37831
| | - C. Patrick Collier
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831
| | - Daniel A. Lutterman
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831
| | - Ying-Zhong Ma
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831
| | - Tessa R. Calhoun
- Department of Chemistry, University of Tennessee, Knoxville, TN, 37996
| | - Benjamin Doughty
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831
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Sanders SE, Vanselous H, Petersen PB. Water at surfaces with tunable surface chemistries. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:113001. [PMID: 29393860 DOI: 10.1088/1361-648x/aaacb5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Aqueous interfaces are ubiquitous in natural environments, spanning atmospheric, geological, oceanographic, and biological systems, as well as in technical applications, such as fuel cells and membrane filtration. Where liquid water terminates at a surface, an interfacial region is formed, which exhibits distinct properties from the bulk aqueous phase. The unique properties of water are governed by the hydrogen-bonded network. The chemical and physical properties of the surface dictate the boundary conditions of the bulk hydrogen-bonded network and thus the interfacial properties of the water and any molecules in that region. Understanding the properties of interfacial water requires systematically characterizing the structure and dynamics of interfacial water as a function of the surface chemistry. In this review, we focus on the use of experimental surface-specific spectroscopic methods to understand the properties of interfacial water as a function of surface chemistry. Investigations of the air-water interface, as well as efforts in tuning the properties of the air-water interface by adding solutes or surfactants, are briefly discussed. Buried aqueous interfaces can be accessed with careful selection of spectroscopic technique and sample configuration, further expanding the range of chemical environments that can be probed, including solid inorganic materials, polymers, and water immiscible liquids. Solid substrates can be finely tuned by functionalization with self-assembled monolayers, polymers, or biomolecules. These variables provide a platform for systematically tuning the chemical nature of the interface and examining the resulting water structure. Finally, time-resolved methods to probe the dynamics of interfacial water are briefly summarized before discussing the current status and future directions in studying the structure and dynamics of interfacial water.
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Affiliation(s)
- Stephanie E Sanders
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, United States of America
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Yesudas F, Mero M, Kneipp J, Heiner Z. Vibrational sum-frequency generation spectroscopy of lipid bilayers at repetition rates up to 100 kHz. J Chem Phys 2018; 148:104702. [PMID: 29544264 DOI: 10.1063/1.5016629] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Freeda Yesudas
- School of Analytical Sciences Adlershof, Humboldt Universität zu Berlin, Albert-Einstein-Str. 5-11, 12489 Berlin, Germany
- Department of Chemistry, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
| | - Mark Mero
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Str. 2a, 12489 Berlin, Germany
| | - Janina Kneipp
- School of Analytical Sciences Adlershof, Humboldt Universität zu Berlin, Albert-Einstein-Str. 5-11, 12489 Berlin, Germany
- Department of Chemistry, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
| | - Zsuzsanna Heiner
- School of Analytical Sciences Adlershof, Humboldt Universität zu Berlin, Albert-Einstein-Str. 5-11, 12489 Berlin, Germany
- Department of Chemistry, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany
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21
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Tan J, Luo Y, Ye S. A Highly Sensitive Femtosecond Time-Resolved Sum Frequency Generation Vibrational Spectroscopy System with Simultaneous Measurement of Multiple Polarization Combinations. CHINESE J CHEM PHYS 2017. [DOI: 10.1063/1674-0068/30/cjcp1706114] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Junjun Tan
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yi Luo
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Shuji Ye
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
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22
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Suzuki Y, Nojima Y, Yamaguchi S. Vibrational Coupling at the Topmost Surface of Water Revealed by Heterodyne-Detected Sum Frequency Generation Spectroscopy. J Phys Chem Lett 2017; 8:1396-1401. [PMID: 28294626 DOI: 10.1021/acs.jpclett.7b00312] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Unraveling vibrational coupling is the key to consistently interpret vibrational spectra of complex molecular systems. The vibrational spectrum of the water surface heavily suffers from vibrational coupling, which hinders complete understanding of the molecular structure and dynamics of the water surface. Here we apply heterodyne-detected sum frequency generation spectroscopy to the water surface and accomplish the assignment of a weak vibrational band located at the lower energy side of the free OH stretch. We find that this band is due to a combination mode of the hydrogen-bonded OH stretch and a low-frequency intermolecular vibration, and this combination band appears in the surface vibrational spectrum through anharmonic vibrational coupling that takes place exclusively at the topmost surface.
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Affiliation(s)
- Yudai Suzuki
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University , 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan
| | - Yuki Nojima
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University , 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan
| | - Shoichi Yamaguchi
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University , 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan
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23
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Lee CM, Kafle K, Huang S, Kim SH. Multimodal Broadband Vibrational Sum Frequency Generation (MM-BB-V-SFG) Spectrometer and Microscope. J Phys Chem B 2015; 120:102-16. [PMID: 26718642 DOI: 10.1021/acs.jpcb.5b10290] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A broadband sum frequency generation (BB-SFG) spectrometer with multimodal (MM) capabilities was constructed, which could be routinely reconfigured for tabletop experiments in reflection, transmission, and total internal reflection (TIR) geometries, as well as microscopic imaging. The system was constructed using a Ti:sapphire amplifier (800 nm, pulse width = 85 fs, repetition rate = 2 kHz), an optical parameter amplification (OPA) system for production of broadband IR pulses tunable between 1000 and 4000 cm(-1), and two Fabry-Pérot etalons arranged in series for production of narrowband 800 nm pulses. The key feature allowing the MM operation was the nearly collinear alignment of the visible (fixed, 800 nm) and infrared (tunable, 1000-4000 cm(-1)) pulses which were spatially separated. Physical insights discussed in this paper include the comparison of spectral bandwidth produced with 40 and 85 fs pump beams, the improvement of spectral resolution using etalons, the SFG probe volume in bulk analysis, the normalization of SFG signals, the stitching of multiple spectral segments, and the operation in different modes for air/liquid and adsorbate/solid interfaces, bulk samples, as well as spectral imaging combined with principle component analysis (PCA). The SFG spectral features obtained with the MM-BB-SFG system were compared with those obtained with picosecond-scanning-SFG system and high-resolution BB-SFG system (HR-BB-SFG) for dimethyl sulfoxide, α-pinene, and various samples containing cellulose (purified commercial products, Cladophora cell wall, cotton and flax fibers, and onion epidermis cell wall).
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Affiliation(s)
- Christopher M Lee
- Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Kabindra Kafle
- Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Shixin Huang
- Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Seong H Kim
- Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University , University Park, Pennsylvania 16802, United States
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24
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Wang Z, Fu L, Ma G, Yan ECY. Broad-Bandwidth Chiral Sum Frequency Generation Spectroscopy for Probing the Kinetics of Proteins at Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:11384-98. [PMID: 26196215 PMCID: PMC4625692 DOI: 10.1021/acs.langmuir.5b02100] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 07/20/2015] [Indexed: 05/09/2023]
Abstract
The kinetics of proteins at interfaces plays an important role in biological functions and inspires solutions to fundamental problems in biomedical sciences and engineering. Nonetheless, due to the lack of surface-specific and structural-sensitive biophysical techniques, it still remains challenging to probe protein kinetics in situ and in real time without the use of spectroscopic labels at interfaces. Broad-bandwidth chiral sum frequency generation (SFG) spectroscopy has been recently developed for protein kinetic studies at interfaces by tracking the chiral vibrational signals of proteins. In this article, we review our recent progress in kinetic studies of proteins at interfaces using broad-bandwidth chiral SFG spectroscopy. We illustrate the use of chiral SFG signals of protein side chains in the C-H stretch region to monitor self-assembly processes of proteins at interfaces. We also present the use of chiral SFG signals from the protein backbone in the N-H stretch region to probe the real-time kinetics of proton exchange between protein and water at interfaces. In addition, we demonstrate the applications of spectral features of chiral SFG that are typical of protein secondary structures in both the amide I and the N-H stretch regions for monitoring the kinetics of aggregation of amyloid proteins at membrane surfaces. These studies exhibit the power of broad-bandwidth chiral SFG to study protein kinetics at interfaces and the promise of this technique in research areas of surface science to address fundamental problems in biomedical and material sciences.
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Affiliation(s)
- Zhuguang Wang
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Li Fu
- William R. Wiley Environment Molecular Sciences Laboratory, Pacific Northwest National Laboratory , P.O. Box 999, Richland, Washington 99352, United States
| | - Gang Ma
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, College of Chemistry and Environmental Science, Hebei University , Baoding 071002, China
| | - Elsa C Y Yan
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
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25
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Yan ECY, Wang Z, Fu L. Proteins at Interfaces Probed by Chiral Vibrational Sum Frequency Generation Spectroscopy. J Phys Chem B 2015; 119:2769-85. [DOI: 10.1021/jp508926e] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Elsa C. Y. Yan
- Department of Chemistry, Yale University, New Haven, CT 06511, United States
| | - Zhuguang Wang
- Department of Chemistry, Yale University, New Haven, CT 06511, United States
| | - Li Fu
- Department of Chemistry, Yale University, New Haven, CT 06511, United States
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26
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Yan ECY, Fu L, Wang Z, Liu W. Biological Macromolecules at Interfaces Probed by Chiral Vibrational Sum Frequency Generation Spectroscopy. Chem Rev 2014; 114:8471-98. [DOI: 10.1021/cr4006044] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Elsa C. Y. Yan
- Department of Chemistry, Yale University, 225 Prospect
Street, New Haven, Connecticut 06520, United States
| | - Li Fu
- Department of Chemistry, Yale University, 225 Prospect
Street, New Haven, Connecticut 06520, United States
| | - Zhuguang Wang
- Department of Chemistry, Yale University, 225 Prospect
Street, New Haven, Connecticut 06520, United States
| | - Wei Liu
- Department of Chemistry, Yale University, 225 Prospect
Street, New Haven, Connecticut 06520, United States
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27
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Fu L, Wang Z, Yan ECY. N-H Stretching Modes Around 3300 Wavenumber From Peptide Backbones Observed by Chiral Sum Frequency Generation Vibrational Spectroscopy. Chirality 2014; 26:521-4. [DOI: 10.1002/chir.22306] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 01/13/2014] [Indexed: 12/15/2022]
Affiliation(s)
- Li Fu
- Departmtent of Chemistry; Yale University; New Haven CT
| | - Zhuguang Wang
- Departmtent of Chemistry; Yale University; New Haven CT
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28
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Liu W, Wang Z, Fu L, Leblanc RM, Yan ECY. Lipid compositions modulate fluidity and stability of bilayers: characterization by surface pressure and sum frequency generation spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15022-31. [PMID: 24245525 DOI: 10.1021/la4036453] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Cell membranes are crucial to many biological processes. Because of their complexity, however, lipid bilayers are often used as model systems. Lipid structures influence the physical properties of bilayers, but their interplay, especially in multiple-component lipid bilayers, has not been fully explored. Here, we used the Langmuir-Blodgett method to make mono- and bilayers of 1,2-dihexadecanoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (POPG), and 1-hexadecanoyl-2-(9Z-octadecenoyl)-sn-glycero-3-phospho-L-serine (POPS) as well as their 1:1 binary mixtures. We studied the fluidity, stability, and rigidity of these structures using sum frequency generation (SFG) spectroscopy combined with analyses of surface pressure-area isotherms, compression modulus, and stability. Our results show that single-component bilayers, both saturated and unsaturated, may not be ideal membrane mimics because of their low fluidity and/or stability. However, the binary saturated and unsaturated DPPG/POPG and DPPG/POPS systems show not only high stability and fluidity but also high resistance to changes in surface pressure, especially in the range of 25-35 mN/m, the range typical of cell membranes. Because the ratio of saturated to unsaturated lipids is highly regulated in cells, our results underline the possibility of modulating biological properties using lipid compositions. Also, our use of flat optical windows as solid substrates in SFG experiments should make the SFG method more compatible with other techniques, enabling more comprehensive future surface characterizations of bilayers.
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Affiliation(s)
- Wei Liu
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
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29
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Wang Z, Fu L, Yan ECY. C-H stretch for probing kinetics of self-assembly into macromolecular chiral structures at interfaces by chiral sum frequency generation spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:4077-83. [PMID: 23458423 DOI: 10.1021/la304954h] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Self-assembly of molecules into chiral macromolecular and supramolecular structures at interfaces is important in various fields, such as biomedicine, polymer sciences, material sciences, and supramolecular chemistry. However, probing the kinetics at interfaces remains challenging because it requires a real-time method that has selectivity to both interface and chirality. Here, we introduce an in situ approach of using the C-H stretch as a vibrational probe detected by chiral sum frequency generation spectroscopy (cSFG). We showed that the C-H stretch cSFG signals of an amphiphilic peptide (LK7β) can reveal the kinetics of its self-assembly into chiral β-sheet structures at the air-water interface. The cSFG experiments in conjunction with measurements of surface pressure allow us to propose a mechanism of the self-assembly process, which involves an immediate adsorption of disordered structures followed by a lag phase before the self-assembly into chiral antiparallel β-sheet structures. Our method of using the C-H stretch signals implies a general application of cSFG to study the self-assembly of bioactive, simple organic, and polymeric molecules into chiral macromolecular and supramolecular structures at interfaces, which will be useful in tackling problems, such as protein aggregation, rational design of functional materials, and fabrication of molecular devices.
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Affiliation(s)
- Zhuguang Wang
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
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30
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Fu L, Xiao D, Wang Z, Batista VS, Yan ECY. Chiral Sum Frequency Generation for In Situ Probing Proton Exchange in Antiparallel β-Sheets at Interfaces. J Am Chem Soc 2013; 135:3592-8. [DOI: 10.1021/ja3119527] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Li Fu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Dequan Xiao
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Zhuguang Wang
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Victor S. Batista
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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31
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Prudovsky I, Kumar TKS, Sterling S, Neivandt D. Protein-phospholipid interactions in nonclassical protein secretion: problem and methods of study. Int J Mol Sci 2013; 14:3734-72. [PMID: 23396106 PMCID: PMC3588068 DOI: 10.3390/ijms14023734] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 01/24/2013] [Accepted: 01/25/2013] [Indexed: 12/30/2022] Open
Abstract
Extracellular proteins devoid of signal peptides use nonclassical secretion mechanisms for their export. These mechanisms are independent of the endoplasmic reticulum and Golgi. Some nonclassically released proteins, particularly fibroblast growth factors (FGF) 1 and 2, are exported as a result of their direct translocation through the cell membrane. This process requires specific interactions of released proteins with membrane phospholipids. In this review written by a cell biologist, a structural biologist and two membrane engineers, we discuss the following subjects: (i) Phenomenon of nonclassical protein release and its biological significance; (ii) Composition of the FGF1 multiprotein release complex (MRC); (iii) The relationship between FGF1 export and acidic phospholipid externalization; (iv) Interactions of FGF1 MRC components with acidic phospholipids; (v) Methods to study the transmembrane translocation of proteins; (vi) Membrane models to study nonclassical protein release.
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Affiliation(s)
- Igor Prudovsky
- Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME 04074, USA
| | | | - Sarah Sterling
- Department of Chemical and Biological Engineering, University of Maine, Orono, ME 04469, USA; E-Mails: (S.S.); (D.N.)
| | - David Neivandt
- Department of Chemical and Biological Engineering, University of Maine, Orono, ME 04469, USA; E-Mails: (S.S.); (D.N.)
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32
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Dynamics of excited state electron transfer at a liquid interface using time-resolved sum frequency generation. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.05.054] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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33
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Scheeline A, Behrens RL. Potential of levitated drops to serve as microreactors for biophysical measurements. Biophys Chem 2012; 165-166:1-12. [DOI: 10.1016/j.bpc.2012.03.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 03/18/2012] [Accepted: 03/18/2012] [Indexed: 01/15/2023]
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Isaienko O, Borguet E. Ultra-broadband sum-frequency vibrational spectrometer of aqueous interfaces based on a non-collinear optical parametric amplifier. OPTICS EXPRESS 2012; 20:547-61. [PMID: 22274376 DOI: 10.1364/oe.20.000547] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We describe an ultrabroadband IR-visible sum-frequency (SF) setup that allows simultaneous acquisition of the entire vibrational spectrum of water molecules at mineral surfaces in the OH stretching region without ever tuning the IR laser pulses. Our newly developed 800-nm pumped noncollinear optical parametric amplifier (NOPA) generates broadband mid-IR pulses (~1800-3500 nm, or ~2900 - 6000 cm-1) with bandwidths >600 cm-1 at half-maximum at near 3500 cm-1. Using the ultra-broadband IR NOPA, we constructed a sum-frequency vibrational spectrometer that allowed the acquisition of spectra of the OH stretches of water at hydrophilic and hydrophobic silica surfaces, over the frequency range ~2900 - 3800 cm-1, within 60 s, much shorter than with scanning SFG spectrometers. The ultra-broadband SFG spectrometer reported here can be potentially applied to time-resolved measurements of kinetics at interfaces.
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Affiliation(s)
- Oleksandr Isaienko
- Department of Chemistry, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania, USA
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Amphiphilic adsorption of human islet amyloid polypeptide aggregates to lipid/aqueous interfaces. J Mol Biol 2011; 421:537-47. [PMID: 22210153 DOI: 10.1016/j.jmb.2011.12.035] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Revised: 12/15/2011] [Accepted: 12/17/2011] [Indexed: 11/23/2022]
Abstract
Many amyloid proteins misfold into β-sheet aggregates upon interacting with biomembranes at the onset of diseases, such as Parkinson's disease and type II diabetes. The molecular mechanisms triggering aggregation depend on the orientation of β-sheets at the cell membranes. However, understanding how β-sheets adsorb onto lipid/aqueous interfaces is challenging. Here, we combine chiral sum frequency generation (SFG) spectroscopy and ab initio quantum chemistry calculations based on a divide-and-conquer strategy to characterize the orientation of human islet amyloid polypeptides (hIAPPs) at lipid/aqueous interfaces. We show that the aggregates bind with β-strands oriented at 48° relative to the interface. This orientation reflects the amphiphilic properties of hIAPP β-sheet aggregates and suggests the potential disruptive effect on membrane integrity.
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Fu L, Wang Z, Yan EC. Chiral vibrational structures of proteins at interfaces probed by sum frequency generation spectroscopy. Int J Mol Sci 2011; 12:9404-25. [PMID: 22272140 PMCID: PMC3257137 DOI: 10.3390/ijms12129404] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 12/13/2011] [Accepted: 12/13/2011] [Indexed: 12/04/2022] Open
Abstract
We review the recent development of chiral sum frequency generation (SFG) spectroscopy and its applications to study chiral vibrational structures at interfaces. This review summarizes observations of chiral SFG signals from various molecular systems and describes the molecular origins of chiral SFG response. It focuses on the chiral vibrational structures of proteins and presents the chiral SFG spectra of proteins at interfaces in the C-H stretch, amide I, and N-H stretch regions. In particular, a combination of chiral amide I and N-H stretches of the peptide backbone provides highly characteristic vibrational signatures, unique to various secondary structures, which demonstrate the capacity of chiral SFG spectroscopy to distinguish protein secondary structures at interfaces. On the basis of these recent developments, we further discuss the advantages of chiral SFG spectroscopy and its potential application in various fields of science and technology. We conclude that chiral SFG spectroscopy can be a new approach to probe chiral vibrational structures of protein at interfaces, providing structural and dynamic information to study in situ and in real time protein structures and dynamics at interfaces.
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Affiliation(s)
- Li Fu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06520, USA; E-Mails: (L.F.); (Z.W.)
| | - Zhuguang Wang
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06520, USA; E-Mails: (L.F.); (Z.W.)
| | - Elsa C.Y. Yan
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT, 06520, USA; E-Mails: (L.F.); (Z.W.)
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Fu L, Liu J, Yan ECY. Chiral Sum Frequency Generation Spectroscopy for Characterizing Protein Secondary Structures at Interfaces. J Am Chem Soc 2011; 133:8094-7. [DOI: 10.1021/ja201575e] [Citation(s) in RCA: 206] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Li Fu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Jian Liu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Elsa C. Y. Yan
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, United States
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Holinga GJ, York RL, Onorato RM, Thompson CM, Webb NE, Yoon AP, Somorjai GA. An SFG Study of Interfacial Amino Acids at the Hydrophilic SiO2 and Hydrophobic Deuterated Polystyrene Surfaces. J Am Chem Soc 2011; 133:6243-53. [DOI: 10.1021/ja1101954] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- George J. Holinga
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States, and Materials Science Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Roger L. York
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States, and Materials Science Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Robert M. Onorato
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States, and Materials Science Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Christopher M. Thompson
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States, and Materials Science Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Nic E. Webb
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States, and Materials Science Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Alfred P. Yoon
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States, and Materials Science Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Gabor A. Somorjai
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States, and Materials Science Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
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Bonn M, Bakker HJ, Ghosh A, Yamamoto S, Sovago M, Campen RK. Structural inhomogeneity of interfacial water at lipid monolayers revealed by surface-specific vibrational pump-probe spectroscopy. J Am Chem Soc 2011; 132:14971-8. [PMID: 20882964 DOI: 10.1021/ja106194u] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We report vibrational lifetime measurements of the OH stretch vibration of interfacial water in contact with lipid monolayers, using time-resolved vibrational sum frequency (VSF) spectroscopy. The dynamics of water in contact with four different lipids are reported and are characterized by vibrational relaxation rates measured at 3200, 3300, 3400, and 3500 cm(-1). We observe that the water molecules with an OH frequency ranging from 3300 to 3500 cm(-1) all show vibrational relaxation with a time constant of T(1) = 180 ± 35 fs, similar to what is found for bulk water. Water molecules with OH groups near 3200 cm(-1) show distinctly faster relaxation dynamics, with T(1) < 80 fs. We successfully model the data by describing the interfacial water containing two distinct subensembles in which spectral diffusion is, respectively, rapid (3300-3500 cm(-1)) and absent (3200 cm(-1)). We discuss the potential biological implications of the presence of the strongly hydrogen-bonded, rapidly relaxing water molecules at 3200 cm(-1) that are decoupled from the bulk water system.
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Affiliation(s)
- Mischa Bonn
- FOM Institute AMOLF, Science Park 104, 1098 XG, Amsterdam, The Netherlands
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Fu L, Ma G, Yan ECY. In situ misfolding of human islet amyloid polypeptide at interfaces probed by vibrational sum frequency generation. J Am Chem Soc 2010; 132:5405-12. [PMID: 20337445 DOI: 10.1021/ja909546b] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Kinetic analysis of conformational changes of proteins at interfaces is crucial for understanding many biological processes at membrane surfaces. In this study, we demonstrate that surface-selective sum frequency generation (SFG) spectroscopy can be used to investigate kinetics of conformational changes of proteins at interfaces. We focus on an intrinsically disordered protein, human islet amyloid polypeptide (hIAPP) that is known to misfold into the beta-sheet structure upon interaction with membranes. Using the ssp polarization setting (s-polarized SFG, s-polarized visible, and p-polarized infrared), we observe changes in the amide I spectra of hIAPP at the air/water interface after addition of dipalmitoylphosphoglycerol (DPPG) that correspond to the lipid-induced changes in secondary structures. We also used the chiral-sensitive psp polarization setting to obtain amide I spectra and observed a gradual buildup of the chiral structures that display the vibrational characteristics of parallel beta-sheets. We speculate that the second-order chiral-optical response at the antisymmetric stretch frequency of parallel beta-sheet at 1622 cm(-1) could be a highly characteristic optical property of the beta-sheet aggregates not only for hIAPP, but possibly also for other amyloid proteins. Analyzing the achiral and chiral amide I spectra, we conclude that DPPG induces the misfolding of hIAPP from alpha-helical and random-coil structures to the parallel beta-sheet structure at the air/water interface. We propose that SFG could complement existing techniques in obtaining kinetic and structural information for probing structures and functions of proteins at interfaces.
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Affiliation(s)
- Li Fu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA
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Selective detection of the antigenic polar heads of model lipid membranes supported on metals from their vibrational nonlinear optical response. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.02.061] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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