A Dynamical Transition in the Protein Myoglobin Observed by Infrared Vibrational Echo Experiments

Rector, Kirk D.; Engholm, J.R.; Rella, Chris W.; Hill, John; Dlott, Dana D.; Fayer, M. D.

doi:10.1021/jp983923d

Cited by 47 publications

(77 citation statements)

References 60 publications

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“…Examples include absorption spectra and photon echo experiments on chromophores in low-temperature glasses, 36 where the pure dephasing is caused by two-level system dynamics, 37,38 and possibly IR absorption spectra and vibrational echo experiments on proteins at moderate to low temperatures. 20 The low-temperature and viscosity-independent processes seen in the experiments below fit this model. However as discussed below, the viscosity-dependent portion of the dephasing does not.…”

Section: Experimental Methods and Proceduresmentioning

confidence: 60%

“…(In a third solvent, 95:5 glycerol/water, the data are also identical below T g .) 20,43 The temperature dependence in trehalose is a power law 20 up to ∼200 K ( Figure 1). There is no change in the functional form near 150 K, where the data in EgOH begins to deviate markedly from the low-temperature power law (eq 8).…”

Section: Resultsmentioning

confidence: 99%

“…15 Because of the ability of ligands to move through the protein, in some sense, the protein has liquidlike character at room temperature. 15 Recently, the ultrafast infrared (IR) vibrational echo technique has been applied to the study of the dynamics of myoglobin-CO (Mb-CO) [16][17][18][19][20] and the closely relate protein, hemoglobin-CO. 21 Vibrational echo measurements of the pure dephasing of the CO stretching mode are sensitive to the complex protein dynamics communicated to the CO ligand bound at the active site of the protein. Unlike other ultrafast techniques that involve electronic excitation of chromophores, 22,23 the vibrational echo experiments directly examine fluctuations of protein structure on the ground-state potential energy surface.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Solvent Viscosity on Protein Dynamics: Infrared Vibrational Echo Experiments and Theory

et al. 2001

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The influence of solvent viscosity on the surface and internal structural dynamics of the protein myoglobin is studied using ultrafast infrared vibrational echo measurements of the pure dephasing of the A 1 CO stretching mode of myoglobin-CO (Mb-CO). The dephasing reflects protein structural fluctuations as sensed by the CO ligand bound at the protein's active site. Measurements made as a function of solvent viscosity at 295 K show that the pure dephasing has a marked dependence on viscosity. In addition, the pure dephasing of Mb-CO in the solvents trehalose and 50:50 ethylene glycol:water are compared as a function of temperature T (10-295 K). The pure dephasing data in the two solvents have identical T 1.3 temperature dependences at low temperatures, where both solvents are glassy solids. At higher temperatures, the Mb-CO pure dephasing has a much steeper temperature dependence in ethylene glycol:water, which is a liquid, than in trehalose, which is a glass at all temperatures studied. The steep temperature dependence in liquid ethylene glycol: water is described as a combination of a viscosity-dependent component and a temperature-dependent component. The viscosity-dependent data are analyzed using a theory that connects the fluctuations of the protein surface to the solvent's viscoelastic response. When the solvent's viscosity is lowered, the increased rate of fluctuation of the protein's surface allows more rapid internal protein dynamics, which result in more rapid dephasing. Good agreement is obtained for physically reasonable parameters. The experimental echo decay times are proportional to the cube root of the solvent viscosity η 1/3 . This proportionality is characteristic of protein structural fluctuations that give rise to CO frequency fluctuations that are in the spectral diffusion regime (relatively slow evolution).

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Section: Experimental Methods and Proceduresmentioning

confidence: 60%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of Solvent Viscosity on Protein Dynamics: Infrared Vibrational Echo Experiments and Theory

et al. 2001

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“…Carbonmonoxy-myoglobin (MbCO) has been extensively studied both experimentally [47][48][49][50][51][52][53][54][55][56] and computationally. [57][58][59][60] Myoglobin (Mb) is a small globular heme protein weighing approximately 17 kDa that is found in mammalian muscle tissue.…”

Section: D Vibrational Echo Experiments a Illustration Of The mentioning

confidence: 99%

Probing dynamics of complex molecular systems with ultrafast 2D IR vibrational echo spectroscopy

Finkelstein

Zheng

Ishikawa

et al. 2007

Phys. Chem. Chem. Phys.

148

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Ultrafast 2D IR vibrational echo spectroscopy is described and a number of experimental examples are given. Details of the experimental method including the pulse sequence, heterodyne detection, and determination of the absorptive component of the 2D spectrum are outlined. As an initial example, the 2D spectrum of the stretching mode of CO bound to the protein myoglobin (MbCO) is presented. The time dependence of the 2D spectrum of MbCO, which is caused by protein structural evolution, is presented and its relationship to the frequency-frequency correlation function is described and used to make protein structural assignments based on comparisons to molecular dynamics simulations. The 2D vibrational echo experiments on the protein horseradish peroxidase are presented. The time dependence of the 2D spectra of the enzyme in the free form and with a substrate bound at the active site are compared and used to examine the influence of substrate binding on the protein's structural dynamics. The application of 2D vibrational echo spectroscopy to the study of chemical exchange under thermal equilibrium conditions is described. 2D vibrational echo chemical exchange spectroscopy is applied to the study of formation and dissociation of organic solute-solvent complexes and to the isomerization around a carbon-carbon single bond of an ethane derivative.

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“…In 1993, Fayer's group performed the first ''vibrational echo'' experiments on liquid and glass (10), and later on the protein myoglobin (11), to reveal the structural evolution of these molecules.…”

Section: Infrared Shiftmentioning

confidence: 99%

Profile of Michael D. Fayer

Marino¹

2008

Proc. Natl. Acad. Sci. U.S.A.

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A Dynamical Transition in the Protein Myoglobin Observed by Infrared Vibrational Echo Experiments

Cited by 47 publications

References 60 publications

Effects of Solvent Viscosity on Protein Dynamics: Infrared Vibrational Echo Experiments and Theory

Effects of Solvent Viscosity on Protein Dynamics: Infrared Vibrational Echo Experiments and Theory

Probing dynamics of complex molecular systems with ultrafast 2D IR vibrational echo spectroscopy

Profile of Michael D. Fayer

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