1
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Kumar G, Kellogg M, Dey S, Oliver TAA, Bradforth SE. Unraveling the Photoionization Dynamics of Indole in Aqueous and Ethanol Solutions. J Phys Chem B 2024; 128:4158-4170. [PMID: 38655896 DOI: 10.1021/acs.jpcb.4c01223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The photoionization dynamics of indole, the ultraviolet-B chromophore of tryptophan, were explored in water and ethanol using ultrafast transient absorption spectroscopy with 292, 268, and 200 nm excitation. By studying the femtosecond-to-nanosecond dynamics of indole in two different solvents, a new photophysical model has been generated that explains many previously unsolved facets of indole's complex solution phase photochemistry. Photoionization is only an active pathway for indole in aqueous solution, leading to a reduction in the fluorescence quantum yield in water-rich environments, which is frequently used in biophysical experiments as a key signature of the protein-folded state. Photoionization of indole in aqueous solution was observed for all three pump wavelengths but via two different mechanisms. For 200 nm excitation, electrons are ballistically ejected directly into the bulk solvent. Conversely, 292 and 268 nm excitation populates an admixture of two 1ππ* states, which form a dynamic equilibrium with a tightly bound indole cation and electron-ion pair. The ion pair dissociates on a nanosecond time scale, generating separated solvated electrons and indole cations. The charged species serve as important precursors to triplet indole production and greatly enhance the overall intersystem crossing rate. Our proposed photophysical model for indole in aqueous solution is the most appropriate for describing photoinduced dynamics of tryptophan in polypeptide sequences; tryptophan in aqueous pH 7 solution is zwitterionic, unlike in peptides, and resultantly has a competitive excited state proton transfer pathway that quenches the tryptophan fluorescence.
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Affiliation(s)
- Gaurav Kumar
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Michael Kellogg
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Shivalee Dey
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Thomas A A Oliver
- School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, U.K
| | - Stephen E Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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2
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He L, Tomaník L, Malerz S, Trinter F, Trippel S, Belina M, Slavíček P, Winter B, Küpper J. Specific versus Nonspecific Solvent Interactions of a Biomolecule in Water. J Phys Chem Lett 2023; 14:10499-10508. [PMID: 37970807 PMCID: PMC10683073 DOI: 10.1021/acs.jpclett.3c01763] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 08/23/2023] [Indexed: 11/19/2023]
Abstract
Solvent interactions, particularly hydration, are vital in chemical and biochemical systems. Model systems reveal microscopic details of such interactions. We uncover a specific hydrogen-bonding motif of the biomolecular building block indole (C8H7N), tryptophan's chromophore, in water: a strong localized N-H···OH2 hydrogen bond, alongside unstructured solvent interactions. This insight is revealed from a combined experimental and theoretical analysis of the electronic structure of indole in aqueous solution. We recorded the complete X-ray photoemission and Auger spectrum of aqueous-phase indole, quantitatively explaining all peaks through ab initio modeling. The efficient and accurate technique for modeling valence and core photoemission spectra involves the maximum-overlap method and the nonequilibrium polarizable-continuum model. A two-hole electron-population analysis quantitatively describes the Auger spectra. Core-electron binding energies for nitrogen and carbon highlight the specific interaction with a hydrogen-bonded water molecule at the N-H group and otherwise nonspecific solvent interactions.
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Affiliation(s)
- Lanhai He
- Center
for Free-Electron Laser Science, Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- Institute
of Atomic and Molecular Physics, Jilin University, 130012 Changchun, China
| | - Lukáš Tomaník
- Department
of Physical Chemistry, University of Chemistry
and Technology, Technická 5, 16628 Prague, Czech Republic
| | - Sebastian Malerz
- Molecular
Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Florian Trinter
- Molecular
Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
- Institut
für Kernphysik, Goethe-Universität
Frankfurt, Max-von-Laue-Straße
1, 60438 Frankfurt
am Main, Germany
| | - Sebastian Trippel
- Center
for Free-Electron Laser Science, Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- Center
for Ultrafast Imaging, Universität
Hamburg, Luruper Chaussee
149, 22761 Hamburg, Germany
| | - Michal Belina
- Department
of Physical Chemistry, University of Chemistry
and Technology, Technická 5, 16628 Prague, Czech Republic
| | - Petr Slavíček
- Department
of Physical Chemistry, University of Chemistry
and Technology, Technická 5, 16628 Prague, Czech Republic
| | - Bernd Winter
- Molecular
Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Jochen Küpper
- Center
for Free-Electron Laser Science, Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- Center
for Ultrafast Imaging, Universität
Hamburg, Luruper Chaussee
149, 22761 Hamburg, Germany
- Department
of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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3
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Zhang S, De Leon Rodriguez LM, Li FF, Brimble MA. Recent developments in the cleavage, functionalization, and conjugation of proteins and peptides at tyrosine residues. Chem Sci 2023; 14:7782-7817. [PMID: 37502317 PMCID: PMC10370606 DOI: 10.1039/d3sc02543h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 06/26/2023] [Indexed: 07/29/2023] Open
Abstract
Peptide and protein selective modification at tyrosine residues has become an exploding field of research as tyrosine constitutes a robust alternative to lysine and cysteine-targeted traditional peptide/protein modification protocols. This review offers a comprehensive summary of the latest advances in tyrosine-selective cleavage, functionalization, and conjugation of peptides and proteins from the past three years. This updated overview complements the extensive body of work on site-selective modification of peptides and proteins, which holds significant relevance across various disciplines, including chemical, biological, medical, and material sciences.
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Affiliation(s)
- Shengping Zhang
- Center for Translational Medicine, Shenzhen Bay Laboratory New Zealand
- School of Chemical Sciences, The University of Auckland 23 Symonds St Auckland 1010 New Zealand
- School of Biological Sciences, The University of Auckland 3A Symonds St Auckland 1010 New Zealand
| | | | - Freda F Li
- School of Chemical Sciences, The University of Auckland 23 Symonds St Auckland 1010 New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland 1142 New Zealand
| | - Margaret A Brimble
- School of Chemical Sciences, The University of Auckland 23 Symonds St Auckland 1010 New Zealand
- School of Biological Sciences, The University of Auckland 3A Symonds St Auckland 1010 New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland 1142 New Zealand
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4
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Pastore AJ, Montoya A, Kamat M, Basso KB, Italia JS, Chatterjee A, Drosou M, Pantazis DA, Angerhofer A. Selective incorporation of 5-hydroxytryptophan blocks long range electron transfer in oxalate decarboxylase. Protein Sci 2023; 32:e4537. [PMID: 36482787 PMCID: PMC9801070 DOI: 10.1002/pro.4537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/28/2022] [Accepted: 12/03/2022] [Indexed: 12/13/2022]
Abstract
Oxalate decarboxylase from Bacillus subtilis is a binuclear Mn-dependent acid stress response enzyme that converts the mono-anion of oxalic acid into formate and carbon dioxide in a redox neutral unimolecular disproportionation reaction. A π-stacked tryptophan dimer, W96 and W274, at the interface between two monomer subunits facilitates long-range electron transfer between the two Mn ions and plays an important role in the catalytic mechanism. Substitution of W96 with the unnatural amino acid 5-hydroxytryptophan leads to a persistent EPR signal which can be traced back to the neutral radical of 5-hydroxytryptophan with its hydroxyl proton removed. 5-Hydroxytryptophan acts as a hole sink preventing the formation of Mn(III) at the N-terminal active site and strongly suppresses enzymatic activity. The lower boundary of the standard reduction potential for the active site Mn(II)/Mn(III) couple can therefore be estimated as 740 mV against the normal hydrogen electrode at pH 4, the pH of maximum catalytic efficiency. Our results support the catalytic importance of long-range electron transfer in oxalate decarboxylase while at the same time highlighting the utility of unnatural amino acid incorporation and specifically the use of 5-hydroxytryptophan as an energetic sink for hole hopping to probe electron transfer in redox proteins.
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Affiliation(s)
| | - Alvaro Montoya
- Department of ChemistryUniversity of FloridaGainesvilleFloridaUSA
| | - Manasi Kamat
- Department of ChemistryUniversity of FloridaGainesvilleFloridaUSA
| | - Kari B. Basso
- Department of ChemistryUniversity of FloridaGainesvilleFloridaUSA
| | - James S. Italia
- Department of ChemistryBoston CollegeChestnut HillMassachusettsUSA
| | | | - Maria Drosou
- Max‐Planck‐Institut für KohlenforschungMülheim an der RuhrGermany
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5
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Abstract
Knowledge of the electronic structure of an aqueous solution is a prerequisite to understanding its chemical and biological reactivity and its response to light. One of the most direct ways of determining electronic structure is to use photoelectron spectroscopy to measure electron binding energies. Initially, photoelectron spectroscopy was restricted to the gas or solid phases due to the requirement for high vacuum to minimize inelastic scattering of the emitted electrons. The introduction of liquid-jets and their combination with intense X-ray sources at synchrotrons in the late 1990s expanded the scope of photoelectron spectroscopy to include liquids. Liquid-jet photoelectron spectroscopy is now an active research field involving a growing number of research groups. A limitation of X-ray photoelectron spectroscopy of aqueous solutions is the requirement to use solutes with reasonably high concentrations in order to obtain photoelectron spectra with adequate signal-to-noise after subtracting the spectrum of water. This has excluded most studies of organic molecules, which tend to be only weakly soluble. A solution to this problem is to use resonance-enhanced photoelectron spectroscopy with ultraviolet (UV) light pulses (hν ≲ 6 eV). However, the development of UV liquid-jet photoelectron spectroscopy has been hampered by a lack of quantitative understanding of inelastic scattering of low kinetic energy electrons (≲5 eV) and the impact on spectral lineshapes and positions.In this Account, we describe the key steps involved in the measurement of UV photoelectron spectra of aqueous solutions: photoionization/detachment, electron transport of low kinetic energy electrons through the conduction band, transmission through the water-vacuum interface, and transport through the spectrometer. We also explain the steps we take to record accurate UV photoelectron spectra of liquids with excellent signal-to-noise. We then describe how we have combined Monte Carlo simulations of electron scattering and spectral inversion with molecular dynamics simulations of depth profiles of organic solutes in aqueous solution to develop an efficient and widely applicable method for retrieving true UV photoelectron spectra of aqueous solutions. The huge potential of our experimental and spectral retrieval methods is illustrated using three examples. The first is a measurement of the vertical detachment energy of the green fluorescent protein chromophore, a sparingly soluble organic anion whose electronic structure underpins its fluorescence and photooxidation properties. The second is a measurement of the vertical ionization energy of liquid water, which has been the subject of discussion since the first X-ray photoelectron spectroscopy measurement in 1997. The third is a UV photoelectron spectroscopy study of the vertical ionization energy of aqueous phenol which demonstrates the possibility of retrieving true photoelectron spectra from measurements with contributions from components with different concentration profiles.
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6
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Ungor D, Bélteki R, Horváth K, Dömötör O, Csapó E. Fluorescence Quenching of Tyrosine-Ag Nanoclusters by Metal Ions: Analytical and Physicochemical Assessment. Int J Mol Sci 2022; 23. [PMID: 36077173 DOI: 10.3390/ijms23179775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/20/2022] [Accepted: 08/26/2022] [Indexed: 11/05/2022] Open
Abstract
A new synthesis method is described for the first time to produce silver nanoclusters (AgNCs) by using the tyrosine (Tyr) amino acid. Several important parameters (e.g., molar ratios, initial pH, reaction time etc.) were optimized to reach the highest yield. The formed Tyr-AgNCs show characteristic blue emission at λem = 410 nm, and two dominant fluorescence lifetime components were deconvoluted (τ1 ~ 3.7 and τ2 ~ 4.9 ns). The NCs contained metallic cores stabilized by dityrosine. For possible application, the interactions with several metal ions from the tap water and wastewater were investigated. Among the studied cations, four different ions (Cu2+, Ni2+, Fe3+, and Rh3+) had a dominant effect on the fluorescence of NCs. Based on the detected quenching processes, the limit of detection of the metal ions was determined. Static quenching (formation of a non-luminescent complex) was observed in all cases by temperature-dependent measurements. The calculated thermodynamic parameters showed that the interactions are spontaneous ranked in the following order of strength: Cu2+ > Fe3+ > Rh3+ > Ni2+. Based on the sign and relations of the standard enthalpy (ΔH°) and entropy changes (ΔS°), the dominant forces were also identified.
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7
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Scholz M, Fortune WG, Tau O, Fielding HH. Accurate Vertical Ionization Energy of Water and Retrieval of True Ultraviolet Photoelectron Spectra of Aqueous Solutions. J Phys Chem Lett 2022; 13:6889-6895. [PMID: 35862937 PMCID: PMC9358712 DOI: 10.1021/acs.jpclett.2c01768] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/14/2022] [Indexed: 05/23/2023]
Abstract
Ultraviolet (UV) photoelectron spectroscopy provides a direct way of measuring valence electronic structure; however, its application to aqueous solutions has been hampered by a lack of quantitative understanding of how inelastic scattering of low-energy (<5 eV) electrons in liquid water distorts the measured electron kinetic energy distributions. Here, we present an efficient and widely applicable method for retrieving true UV photoelectron spectra of aqueous solutions. Our method combines Monte Carlo simulations of electron scattering and spectral inversion, with molecular dynamics simulations of depth profiles of organic solutes in aqueous solution. Its application is demonstrated for both liquid water, and aqueous solutions of phenol and phenolate, which are ubiquitous biologically relevant structural motifs.
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8
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Ban L, Tang H, Yoder BL, Signorell R. Time-dependent photoemission from droplets: influence of size and charge on the photophysics near the surface. Faraday Discuss 2022; 236:461-484. [PMID: 35507329 PMCID: PMC9408814 DOI: 10.1039/d1fd00108f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Photoemission from submicrometer droplets containing a mixture of dioctyl phthalate and dioctyl sebacate was investigated by femtosecond and nanosecond photoionization. Photoelectron spectra recorded after ionization with single 4.7 eV femtosecond or nanosecond laser pulses showed marked differences between the two cases. These differences were attributed to ionization of long-lived states which only occurred within the duration of the nanosecond pulse. The tentative assignment of the long-lived states to dioctyl phthalate triplet states is discussed. A nanosecond–femtosecond pump–probe scheme using 4.7 eV (pump) and 3.1 eV (probe) pulses was used to investigate the decay dynamics of these long-lived states. The dynamics showed an accelerated decay rate at higher dioctyl phthalate concentrations. Furthermore, the dependence of the decay dynamics on droplet size and charge was investigated. The decay of the long-lived states was found to be faster in smaller droplets as well as in neutral droplets compared with both positively and negatively charged droplets. Possible mechanisms to explain these observations and the dominance of contributions from the droplets surface are discussed. Time-resolved photoemission spectroscopy is used to study the photophysics of droplets containing dioctyl phthalate. Long-lived excited states survive longer at lower phthalate concentrations, and in larger or electrically charged droplets.![]()
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Affiliation(s)
- Loren Ban
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland.
| | - Hanchao Tang
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland.
| | - Bruce L Yoder
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland.
| | - Ruth Signorell
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland.
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9
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Bin Mohd Yusof MS, Siow JX, Yang N, Chan WX, Loh ZH. Spectroscopic observation and ultrafast coherent vibrational dynamics of the aqueous phenylalanine radical. Phys Chem Chem Phys 2022; 24:2800-2812. [PMID: 35048090 DOI: 10.1039/d1cp04326a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The phenylalanine radical (Phe˙) has been proposed to mediate biological electron transport (ET) and exhibit long-lived electronic coherences following attosecond photoionization. However, the coupling of ultrafast structural reorganization to the oxidation/ionization of biomolecules such as phenylalanine remains unexplored. Moreover, studies of ET involving Phe˙ are hindered by its hitherto unobserved electronic spectrum. Here, we report the spectroscopic observation and coherent vibrational dynamics of aqueous Phe˙, prepared by sub-6 fs photodetachment of phenylalaninate anions. Sub-picosecond transient absorption spectroscopy reveals the ultraviolet absorption signature of Phe˙. Ultrafast structural reorganization drives coherent vibrational motion involving nine fundamental frequencies and one overtone. DFT calculations rationalize the absence of the decarboxylation reaction, a photodegradation pathway previously identified for Phe˙. Our findings guide the interpretation of future attosecond experiments aimed at elucidating coherent electron motion in photoionized aqueous biomolecules and pave way for the spectroscopic identification of Phe˙ in studies of biological ET.
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Affiliation(s)
- Muhammad Shafiq Bin Mohd Yusof
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Jing Xuan Siow
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Ningchen Yang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Wei Xin Chan
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
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10
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Bin Mohd Yusof MS, Debnath T, Loh ZH. Observation of intra- and intermolecular vibrational coherences of the aqueous tryptophan radical induced by photodetachment. J Chem Phys 2021; 155:134306. [PMID: 34624987 DOI: 10.1063/5.0067335] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The study of the photodetachment of amino acids in aqueous solution is pertinent to the understanding of elementary processes that follow the interaction of ionizing radiation with biological matter. In the case of tryptophan, the tryptophan radical that is produced by electron ejection also plays an important role in numerous redox reactions in biology, although studies of its ultrafast molecular dynamics are limited. Here, we employ femtosecond optical pump-probe spectroscopy to elucidate the ultrafast structural rearrangement dynamics that accompany the photodetachment of the aqueous tryptophan anion by intense, ∼5-fs laser pulses. The observed vibrational wave packet dynamics, in conjunction with density functional theory calculations, identify the vibrational modes of the tryptophan radical, which participate in structural rearrangement upon photodetachment. Aside from intramolecular vibrational modes, our results also point to the involvement of intermolecular modes that drive solvent reorganization about the N-H moiety of the indole sidechain. Our study offers new insight into the ultrafast molecular dynamics of ionized biomolecules and suggests that the present experimental approach can be extended to investigate the photoionization- or photodetachment-induced structural dynamics of larger biomolecules.
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Affiliation(s)
- Muhammad Shafiq Bin Mohd Yusof
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Tushar Debnath
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
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11
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Bin Mohd Yusof MS, Lim YL, Loh ZH. Ultrafast vibrational wave packet dynamics of the aqueous tyrosyl radical anion induced by photodetachment. Phys Chem Chem Phys 2021; 23:18525-18534. [PMID: 34581329 DOI: 10.1039/d1cp02975d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ultrafast dynamics triggered by the photodetachment of the tyrosinate dianion in aqueous environment shed light on the elementary processes that accompany the interaction of ionizing radiation with biological matter. Photodetachment of the tryosinate dianion yields the tyrosyl radical anion, an important intermediate in biological redox reactions, although the study of its ultrafast dynamics is limited. Here, we utilize femtosecond optical pump-probe spectroscopy to investigate the ultrafast structural reorganization dynamics that follow the photodetachment of the tyrosinate dianion in aqueous solution. Photodetachment of the tyrosinate dianion leads to vibrational wave packet motion along seven vibrational modes that are coupled to the photodetachment process. The vibrational modes are assigned with the aid of density functional theory (DFT) calculations. Our results offer a glimpse of the elementary dynamics of ionized biomolecules and suggest the possibility of extending this approach to investigate the ionization-induced structural rearrangement of other aromatic amino acids and larger biomolecules.
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Affiliation(s)
- Muhammad Shafiq Bin Mohd Yusof
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Yong Liang Lim
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore.
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12
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Weng G, Vlček V. Efficient treatment of molecular excitations in the liquid phase environment via stochastic many-body theory. J Chem Phys 2021; 155:054104. [PMID: 34364336 DOI: 10.1063/5.0058410] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Accurate predictions of charge excitation energies of molecules in the disordered condensed phase are central to the chemical reactivity, stability, and optoelectronic properties of molecules and critically depend on the specific environment. Herein, we develop a stochastic GW method for calculating these charge excitation energies. The approach employs maximally localized electronic states to define the electronic subspace of a molecule and the rest of the system, both of which are randomly sampled. We test the method on three solute-solvent systems: phenol, thymine, and phenylalanine in water. The results are in excellent agreement with the previous high-level calculations and available experimental data. The stochastic calculations for supercells containing up to 1000 electrons representing the solvated systems are inexpensive and require ≤1000 central processing unit hrs. We find that the coupling with the environment accounts for ∼40% of the total correlation energy. The solvent-to-solute feedback mechanism incorporated in the molecular correlation term causes up to 0.6 eV destabilization of the quasiparticle energy. Simulated photo-emission spectra exhibit red shifts, state-degeneracy lifting, and lifetime shortening. Our method provides an efficient approach for an accurate study of excitations of large molecules in realistic condensed phase environments.
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Affiliation(s)
- Guorong Weng
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, USA
| | - VojtĚch Vlček
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, USA
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13
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Pastore AJ, Teo RD, Montoya A, Burg MJ, Twahir UT, Bruner SD, Beratan DN, Angerhofer A. Oxalate decarboxylase uses electron hole hopping for catalysis. J Biol Chem 2021; 297:100857. [PMID: 34097877 PMCID: PMC8254039 DOI: 10.1016/j.jbc.2021.100857] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 05/28/2021] [Accepted: 06/03/2021] [Indexed: 01/16/2023] Open
Abstract
The hexameric low-pH stress response enzyme oxalate decarboxylase catalyzes the decarboxylation of the oxalate mono-anion in the soil bacterium Bacillus subtilis. A single protein subunit contains two Mn-binding cupin domains, and catalysis depends on Mn(III) at the N-terminal site. The present study suggests a mechanistic function for the C-terminal Mn as an electron hole donor for the N-terminal Mn. The resulting spatial separation of the radical intermediates directs the chemistry toward decarboxylation of the substrate. A π-stacked tryptophan pair (W96/W274) links two neighboring protein subunits together, thus reducing the Mn-to-Mn distance from 25.9 Å (intrasubunit) to 21.5 Å (intersubunit). Here, we used theoretical analysis of electron hole-hopping paths through redox-active sites in the enzyme combined with site-directed mutagenesis and X-ray crystallography to demonstrate that this tryptophan pair supports effective electron hole hopping between the C-terminal Mn of one subunit and the N-terminal Mn of the other subunit through two short hops of ∼8.5 Å. Replacement of W96, W274, or both with phenylalanine led to a large reduction in catalytic efficiency, whereas replacement with tyrosine led to recovery of most of this activity. W96F and W96Y mutants share the wildtype tertiary structure. Two additional hole-hopping networks were identified leading from the Mn ions to the protein surface, potentially protecting the enzyme from high Mn oxidation states during turnover. Our findings strongly suggest that multistep hole-hopping transport between the two Mn ions is required for enzymatic function, adding to the growing examples of proteins that employ aromatic residues as hopping stations.
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Affiliation(s)
- Anthony J Pastore
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | - Ruijie D Teo
- Department of Chemistry, Duke University, Durham, North Carolina, USA
| | - Alvaro Montoya
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | - Matthew J Burg
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | - Umar T Twahir
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | - Steven D Bruner
- Department of Chemistry, University of Florida, Gainesville, Florida, USA
| | - David N Beratan
- Department of Chemistry, Duke University, Durham, North Carolina, USA.
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14
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Zhao T, Cheang TY, Chong HB, Ling C, Lu XJ, Li CC, Fang XX, Ma LB, Wang G, Xu AW. Biomolecular l-tryptophan as a hole mediator anchored on g-C 3N 4 exhibits remarkably enhanced photocatalytic H 2 evolution. Catal Sci Technol 2021; 11:4776-4782. [DOI: 10.1039/d1cy00325a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel g-C3N4-based composite coupled with levorotatory-tryptophan restrains the recombination of photogenerated holes and electrons, exhibiting enhanced photocatalytic H2 production.
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15
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Abdelhameed SAM, Vandebroek L, de Azambuja F, Parac-Vogt TN. Redox Activity of Ce(IV)-Substituted Polyoxometalates toward Amino Acids and Peptides. Inorg Chem 2020; 59:10569-10577. [DOI: 10.1021/acs.inorgchem.0c00993] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
| | - Laurens Vandebroek
- KU Leuven, Department of Chemistry, Celestijnenlaan 200F, 3001 Leuven, Belgium
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16
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Ban L, Gartmann TE, Yoder BL, Signorell R. Low-Energy Electron Escape from Liquid Interfaces: Charge and Quantum Effects. Phys Rev Lett 2020; 124:013402. [PMID: 31976689 DOI: 10.1103/physrevlett.124.013402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Indexed: 05/27/2023]
Abstract
The high surface sensitivity and controlled surface charge state of submicron sized droplets is exploited to study low-energy electron transport through liquid interfaces using photoelectron imaging. Already a few charges on a droplet are found to modify the photoelectron images significantly. For narrow escape barriers, the comparison with an electron scattering model reveals pronounced quantum effects in the form of above-barrier reflections at electron kinetic energies below about 1 eV. The observed susceptibility to the characteristics of the electron escape barrier might provide access to these properties for liquid interfaces, which are generally difficult to investigate.
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Affiliation(s)
- Loren Ban
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland
| | - Thomas E Gartmann
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland
| | - Bruce L Yoder
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland
| | - R Signorell
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland
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17
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Henley A, Riley J, Wang B, Fielding HH. An experimental and computational study of the effect of aqueous solution on the multiphoton ionisation photoelectron spectrum of phenol. Faraday Discuss 2020; 221:202-218. [DOI: 10.1039/c9fd00079h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We revisit the photoelectron spectroscopy of aqueous phenol in an effort to improve our understanding of the impact of inhomogeneous broadening and inelastic scattering on solution-phase photoelectron spectra.
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Affiliation(s)
- Alice Henley
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
| | - Jamie W. Riley
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
| | - Bingxing Wang
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
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18
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Riley JW, Wang B, Parkes MA, Fielding HH. Design and characterization of a recirculating liquid-microjet photoelectron spectrometer for multiphoton ultraviolet photoelectron spectroscopy. Rev Sci Instrum 2019; 90:083104. [PMID: 31472605 DOI: 10.1063/1.5099040] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/20/2019] [Indexed: 06/10/2023]
Abstract
A new recirculating liquid-microjet photoelectron spectrometer for multiphoton ultraviolet photoelectron spectroscopy is described. A recirculating system is essential for studying samples that are only available in relatively small quantities. The reduction in background pressure when using the recirculating system compared to a liquid-nitrogen cold-trap results in a significant improvement in the quality of the photoelectron spectra. Moreover, the recirculating system results in a negligible streaming potential. The instrument design, operation, and characterization are described in detail, and its performance is illustrated by comparing a photoelectron spectrum of aqueous phenol recorded using the recirculating system with one recorded using a liquid nitrogen cold-trap.
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Affiliation(s)
- Jamie W Riley
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Bingxing Wang
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Michael A Parkes
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Helen H Fielding
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
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19
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Garreau M, Le Vaillant F, Waser J. C‐Terminal Bioconjugation of Peptides through Photoredox Catalyzed Decarboxylative Alkynylation. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201901922] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Marion Garreau
- Laboratory of Catalysis and Organic Synthesis Ecole Polytechnique Fédérale de Lausanne EPFL SB ISIC LCSO, BCH 4306 1015 Lausanne Switzerland
| | - Franck Le Vaillant
- Laboratory of Catalysis and Organic Synthesis Ecole Polytechnique Fédérale de Lausanne EPFL SB ISIC LCSO, BCH 4306 1015 Lausanne Switzerland
| | - Jerome Waser
- Laboratory of Catalysis and Organic Synthesis Ecole Polytechnique Fédérale de Lausanne EPFL SB ISIC LCSO, BCH 4306 1015 Lausanne Switzerland
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20
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Garreau M, Le Vaillant F, Waser J. C‐Terminal Bioconjugation of Peptides through Photoredox Catalyzed Decarboxylative Alkynylation. Angew Chem Int Ed Engl 2019; 58:8182-8186. [DOI: 10.1002/anie.201901922] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Indexed: 01/06/2023]
Affiliation(s)
- Marion Garreau
- Laboratory of Catalysis and Organic Synthesis Ecole Polytechnique Fédérale de Lausanne EPFL SB ISIC LCSO, BCH 4306 1015 Lausanne Switzerland
| | - Franck Le Vaillant
- Laboratory of Catalysis and Organic Synthesis Ecole Polytechnique Fédérale de Lausanne EPFL SB ISIC LCSO, BCH 4306 1015 Lausanne Switzerland
| | - Jerome Waser
- Laboratory of Catalysis and Organic Synthesis Ecole Polytechnique Fédérale de Lausanne EPFL SB ISIC LCSO, BCH 4306 1015 Lausanne Switzerland
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21
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Kumar G, Roy A, McMullen RS, Kutagulla S, Bradforth SE. The influence of aqueous solvent on the electronic structure and non-adiabatic dynamics of indole explored by liquid-jet photoelectron spectroscopy. Faraday Discuss 2018; 212:359-381. [DOI: 10.1039/c8fd00123e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved photoelectron spectroscopy (TRPES) in a liquid micro-jet is implemented here to investigate the influence of water on the electronic structure and dynamics of indole, the chromophore of the amino acid tryptophan.
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Affiliation(s)
- Gaurav Kumar
- Department of Chemistry
- University of Southern California
- Los Angeles
- USA
| | - Anirban Roy
- Department of Chemistry
- University of Southern California
- Los Angeles
- USA
| | - Ryan S. McMullen
- Department of Chemistry
- University of Southern California
- Los Angeles
- USA
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