Resonance Raman De-Enhancement Caused by Excited State Mixed Valence

Wang, Xianghuai; Valverde-Aguilar, Guadalupe; Weaver, Michael N.; Nelsen, Stephen F.; Zink, Jeffrey I.

doi:10.1021/jp071203d

Cited by 22 publications

(10 citation statements)

References 48 publications

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“…Resonance Raman excitation profiles indicate that the pronounced vibrational bands all derive from a single species via excitation into one electronic transition (Figure S4B). 61 Attempts to obtain resonance Raman spectra of R2lox prior to photoconversion were unsuccessful, as even low photon fluxes caused this change to occur during spectral collection, and the vast amounts of sample that would be required for a single-pass experiment are prohibitive.…”

Section: Resultsmentioning

confidence: 99%

Driving Protein Conformational Changes with Light: Photoinduced Structural Rearrangement in a Heterobimetallic Oxidase

et al. 2018

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The heterobimetallic R2lox protein binds both manganese and iron ions in a site-selective fashion and activates oxygen, ultimately performing C-H bond oxidation to generate a tyrosine-valine cross-link near the active site. In this work, we demonstrate that, following assembly, R2lox undergoes photoinduced changes to the active site geometry and metal coordination motif. Through spectroscopic, structural, and mass spectrometric characterization, the photoconverted species is found to consist of a tyrosinate-bound iron center following light-induced decarboxylation of a coordinating glutamate residue and cleavage of the tyrosine-valine cross-link. This process occurs with high quantum efficiencies (Φ = 3%) using violet and near-ultraviolet light, suggesting that the photodecarboxylation is initiated via ligand-to-metal charge transfer excitation. Site-directed mutagenesis and structural analysis suggest that the cross-linked tyrosine-162 is the coordinating residue. One primary product is observed following irradiation, indicating potential use of this class of proteins, which contains a putative substrate channel, for controlled photoinduced decarboxylation processes, with relevance for in vivo functionality of R2lox as well as application in environmental remediation.

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Section: Resultsmentioning

confidence: 99%

Driving Protein Conformational Changes with Light: Photoinduced Structural Rearrangement in a Heterobimetallic Oxidase

et al. 2018

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“…In this format, the gradient approximation is limited to resonance with a single electronic state, neglecting any mode enhancement due to the additive effects of resonance with nearby excited states. Similarly, this approach does not account for quantum interference caused by allowed transitions to multiple electronic states or population transfer due to nonadiabatic coupling between states, which result in resonance de-enhancement. , Reduced enhancement due to homogeneous broadening, most significant for low frequency modes, is also neglected in this approach. ,, …”

Section: Theorymentioning

confidence: 99%

Excited State Resonance Raman of Flavin Mononucleotide: Comparison of Theory and Experiment

et al. 2021

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Blue light absorbing flavoproteins play important roles in a variety of photobiological processes. Consequently, there have been numerous investigations of their excited state structure and dynamics, in particular by time-resolved vibrational spectroscopy. The isoalloxazine chromophore of the flavoprotein cofactors has been studied in detail by time-resolved Raman, lending it a benchmark status for mode assignments in excited electronic states of large molecules. However, detailed comparisons of calculated and measured spectra have proven challenging, as there are many more modes calculated than are observed, and the role of resonance enhancement is difficult to characterize in excited electronic states. Here we employ a recently developed approach due to Elles and co-workers (J. Phys. Chem. A 2018, 122, 8308−8319) for the calculation of resonance-enhanced Raman spectra of excited states and apply it to the lowest singlet and triplet excited states of the isoalloxazine chromophore. There is generally good agreement between calculated and observed enhancements, which allows assignment of vibrational bands of the flavoprotein cofactors to be refined. However, some prominently enhanced bands are found to be absent from the calculations, suggesting the need for further development of the theory.

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“…The SERS spectrum of anthracene on the CD-SH functional AgNPs shows five main bands, at 395, 754, 1403, 1482 and 1558 cm À1 ; their assignments are listed in Table 1. 20,34,35 As to pyrene, the SERS spectrum yields six distinctive bands, allowing us to identify pyrene. The assignments of the pyrene bands at 408, 593, 1241, 1406, 1595 and 1628 cm À1 are given in Table 1.…”

Section: Distinction Between Anthracene and Pyrene By Their Sers Spectramentioning

confidence: 99%

Sensing of polycyclic aromatic hydrocarbons with cyclodextrin inclusion complexes on silver nanoparticles by surface-enhanced Raman scattering

Xie

Wang

Han

et al. 2010

Analyst

119

101

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We have developed a new type of surface-enhanced Raman scattering (SERS) substrate that consists of per-6-deoxy-(6-thio)-beta-cyclodextrin (CD-SH) modified by silver nanoparticles (AgNPs) for sensing of polycyclic aromatic hydrocarbons (PAHs), a kind of environmental pollutant, with very low affinity to metallic surfaces. The designed system can induce some PAH molecules (anthracene and pyrene) to insert into the hydrophobic cavity of beta-CD, which enables one to detect SERS of PAHs because the analytes are very close to the AgNPs surface, which is the zone of electromagnetic enhancement. The measured spectra can easily distinguish the two kinds of PAH compounds in a mixture by their own characteristic peaks. In addition, we carried out selective detection of PAHs by SERS of the inclusion complexes with different concentrations in the presence of CD-SH functionalized AgNPs. Moreover, this sensing platform has been applied to quantitative detection of PAH in a mixture consisting of anthracene and pyrene. The CD molecule has the feature of high selectivity due to its size of cavity, significantly enhancing the sensitivity of the system after CD-SH adsorbs on AgNPs via the terminal thiol. This proposed method for the detection of PAHs holds great potential in environmental analytical chemistry.

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Resonance Raman De-Enhancement Caused by Excited State Mixed Valence

Cited by 22 publications

References 48 publications

Driving Protein Conformational Changes with Light: Photoinduced Structural Rearrangement in a Heterobimetallic Oxidase

Driving Protein Conformational Changes with Light: Photoinduced Structural Rearrangement in a Heterobimetallic Oxidase

Excited State Resonance Raman of Flavin Mononucleotide: Comparison of Theory and Experiment

Sensing of polycyclic aromatic hydrocarbons with cyclodextrin inclusion complexes on silver nanoparticles by surface-enhanced Raman scattering

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