Model-Independent Estimation of the Photokinetic Transfer Matrix from Matrix-Formatted Frequency-Domain Fluorescence

Neal, Sharon L.

doi:10.1021/jp9701707

Cited by 9 publications

(15 citation statements)

References 29 publications

(42 reference statements)

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“…PMD analysis is a curve resolution method that has been previously used to evaluate frequency and time domain data of solvatochromic fluorescent molecules and the interaction of excited states, revealing both GSH and ESR type photokinetics. 31,32,36,37 PMD analysis constructs a photokinetic matrix, K, based on the assumption that all emission decays monoexponentially from a given electronic state:…”

Section: Discussionmentioning

confidence: 99%

Multivariate analysis of emission decay matrices for distinguishing ground state heterogeneity and excited state reactions of tryptophan

Roach

2011

Analyst

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The amino acid tryptophan displays emission solvatochromism, an emission maximum that shifts with solvent polarity, which is often used in protein studies to indicate local environment hydrophobicity. Use of tryptophan solvatochromism in time-resolved protein studies has traditionally been complicated due to the undescribed photokinetics that result in a characteristic multiexponential emission decay. For the first time, by application of the photokinetic matrix decomposition (PMD) multivariate curve resolution method to time-resolved emission decay (TRED) data, a distinguishment between ground state heterogeneous (GSH) and excited state reaction (ESR) type photokinetics of tryptophan in solution is made possible. It is found that molecular tryptophan displays two emission spectra that decay independently, suggesting GSH type photokinetics, one at 347 nm with a lifetime of 0.5 ns and one at 363 nm with a lifetime of 3.1 ns. When tryptophan is incorporated into a peptide, mastoparan X, the data similarly contain two emission spectra that decay independently, but are shifted in wavelength. Photobleaching experiments confirm that the PMD method is sensitive to tryptophan emission quenching, and therefore may be applied to determine the photokinetics of tryptophan that occur in proteins. Future applications of PMD analysis of tryptophan TRED data as a bioanalytical tool for further characterizing dynamic protein processes are discussed.

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Section: Discussionmentioning

confidence: 99%

Multivariate analysis of emission decay matrices for distinguishing ground state heterogeneity and excited state reactions of tryptophan

Roach

2011

Analyst

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“…The derivation of the method from this relationship has been discussed fully elsewhere and is only summarized here. 12 When the kinetic equations governing the decay of n excitedstate fluorophores are written as a system of coupled first-order differential equations, i.e.…”

Section: Theorymentioning

confidence: 99%

“…Further details of this method are described elsewhere. 12,13 Any matrix D ˜can be factored into principal components:…”

Section: Theorymentioning

confidence: 99%

“…The basis of nonparametric frequency domain analysis is the linear relationship between the derivative of a frequency domain decay and the photokinetic transfer matrix governing the time evolution of excited-state species. The derivation of the method from this relationship has been discussed fully elsewhere and is only summarized here …”

Section: Theorymentioning

confidence: 99%

“…Recently, a more general model-independent approach to the analysis of multicomponent fluorescence decays has been developed. It has been demonstrated that it is possible to analyze multidimensional, i.e., wavelength-resolved, decays in the frequency domain without model assumptions, 12 even if the mixture components are participating in excited-state reactions 13 because the Fourier coefficients of the decay are linearly related to the photokinetic transfer matrix describing the time evolution of the excited-state species. 14 This development has two important benefits.…”

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confidence: 99%

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Frequency Domain Multidimensional Fluorescence: A Route to Model-Independent Fluorescence Decay Analysis

Neal

1997

Anal. Chem.

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A multivariate method for analyzing complex fluorescence decays without model assumptions is described. This method is applicable to the decays of mixtures of spectrally distinct fluorophores. The method does not require specific information concerning the component spectra or lifetimes, but such information can be used when it is available. The decay is analyzed as the complex quantum yield (a function of the steady-state intensity, modulation ratio, and phase angle) measured as a function of modulation frequency and, in most cases, emission wavelength. When the spectra of the mixture components are known, the frequency domain decays of the components can be calculated from complex quantum yield matrices measured at all or selected wavelengths. Matrices describing component photokinetics and relative concentrations are calculated from the frequency domain decays. When the component emission spectra are not known, complex quantum yield matrices can be factored into the emission spectra and frequency domain decays of the sample components via principal components analysis of the matrix. In this paper, the principles of frequency domain decay analysis are discussed. In particular, the variation of the analysis procedure with the amount of data acquired and the extent of the analyst's knowledge of the sample components are described. These procedural variations are illustrated by the analysis of simulated decays and the decays of mixtures of polynuclear aromatic hydrocarbons in isotropic and microheterogeneous solution.

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Ultraviolet and Visible Molecular Absorption and Fluorescence Data Analysis

Neal

2000

Encyclopedia of Analytical Chemistry

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This article is a survey of the data analysis methods that have been applied to ultraviolet (UV) and visible molecular absorbance and fluorescence measurements. The section after the Introduction reviews the principles of the most widely used types of absorbance and fluorescence measurements. These include steady‐state, dynamic and multidimensional measurements. After a brief description of absorption and fluorescence instruments, three classes of data analysis methods for molecular absorbance and fluorescence are described: regression methods, decay analysis and matrix factorization methods. Result validation, software alternatives and future developments are discussed in short sections at the end of the article. A short matrix algebra primer is provided as an appendix to the article.

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Model-Independent Estimation of the Photokinetic Transfer Matrix from Matrix-Formatted Frequency-Domain Fluorescence

Cited by 9 publications

References 29 publications

Multivariate analysis of emission decay matrices for distinguishing ground state heterogeneity and excited state reactions of tryptophan

Multivariate analysis of emission decay matrices for distinguishing ground state heterogeneity and excited state reactions of tryptophan

Frequency Domain Multidimensional Fluorescence: A Route to Model-Independent Fluorescence Decay Analysis

Ultraviolet and Visible Molecular Absorption and Fluorescence Data Analysis

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