Heme-Solvent Coupling: A Mössbauer Study of Myoglobin in Sucrose

Lichtenegger, Helga C.; Doster, Wolfgang; Kleinert, T.; Birk, Alexander; Sepioł, B.; Vogl, G.

doi:10.1016/s0006-3495(99)77208-5

Cited by 84 publications

(85 citation statements)

References 45 publications

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“…It was first discovered by researchers using Mö ssbauer spectroscopy to probe haem-iron movements in myoglobin and has subsequently been studied by other experimental techniques including neutron scattering (Doster et al, 1989;Ferrand et al, 1993) and X-ray crystallography (see x4 below). In addition to its importance as a prominent feature in the low-temperature physics of biological macromolecules, the dynamical transition has been linked to the onset of biological activity (Rasmussen et al, 1992;Lichtenegger et al, 1999;Ostermann et al, 2000). However, certain enzymes are active below the dynamical transition (Daniel et al, 1998), or are at least able to undergo part of their catalytic cycle (Heyes et al, 2002;Durin et al, 2009).…”

Section: Protein and Solvent Dynamics As A Function Of Cryo-temperaturementioning

confidence: 99%

Temperature-dependent macromolecular X-ray crystallography

Weik

Colletier

2010

Acta Crystallogr D Biol Crystallogr

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X-ray crystallography provides structural details of biological macromolecules. Whereas routine data are collected close to 100 K in order to mitigate radiation damage, more exotic temperature-controlled experiments in a broader temperature range from 15 K to room temperature can provide both dynamical and structural insights. Here, the dynamical behaviour of crystalline macromolecules and their surrounding solvent as a function of cryo-temperature is reviewed. Experimental strategies of kinetic crystallography are discussed that have allowed the generation and trapping of macromolecular intermediate states by combining reaction initiation in the crystalline state with appropriate temperature profiles. A particular focus is on recruiting X-ray-induced changes for reaction initiation, thus unveiling useful aspects of radiation damage, which otherwise has to be minimized in macromolecular crystallography.

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Section: Protein and Solvent Dynamics As A Function Of Cryo-temperaturementioning

confidence: 99%

Temperature-dependent macromolecular X-ray crystallography

Weik

Colletier

2010

Acta Crystallogr D Biol Crystallogr

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“…Anyhow, irrespective of the exact physical origin of the dynamic crossover most results suggest that the process below the crossover temperature should be considered as a secondary process, distinguished from the cooperative and viscosity related α-relaxation, which is unobservable with both dielectric spectroscopy and NMR techniques [10], at least below the crossover temperature [6,7]. If the α-relaxation of the hydration water disappears, due to confinement effects, at the crossover temperature, it should have an impact on protein dynamics, and consequently also on protein function, since it has been shown that protein conformational changes [13,14], and escape of carbon monoxide (CO) out of the heme cavity in myoglobin [15], cannot occur without the viscosity related (α) relaxation in the surrounding solvent. Thus, in this case, such large scale protein fluctuations will disappear at the dynamic crossover temperature of the solvent, giving rise to a glass-like transition of the protein-solvent system.…”

Section: Introductionmentioning

confidence: 99%

The protein glass transition as measured by dielectric spectroscopy and differential scanning calorimetry

Jansson¹,

Swenson

2010

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics

100

102

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The glass transition and its related dynamics of myoglobin in water and in a water-glycerol mixture have been investigated by dielectric spectroscopy and differential scanning calorimetry (DSC). For all samples, the DSC measurements display a glass transition that extends over a large temperature range. Both the temperature of the transition and its broadness decrease rapidly with increasing amount of solvent in the system. The dielectric measurements show several dynamical processes, due to both protein and solvent relaxations, and in the case of pure water as solvent the main protein process (which most likely is due to conformational changes of the protein structure) exhibits a dynamic glass transition (i.e. reaches a relaxation time of 100 s) at about the same temperature as the calorimetric glass transition temperature T g is found. This glass transition is most likely caused by the dynamic crossover and the associated vanishing of the α-relaxation of the main water relaxation, although it does not contribute to the calorimetric T g . This is in contrast to myoglobin in water-glycerol, where the main solvent relaxation makes the strongest contribution to the calorimetric glass transition. For all samples it is clear that several proteins processes are involved in the calorimetric glass transition and the broadness of the transition depends on how much these different relaxations are separated in time.

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“…Thus, the solvent plays a crucial role in the dynamic transition in biopolymers. This observation led to a suggestion by many authors that proteins are ''slaves'' to the solvent (24). Despite many experimental studies, the nature of the dynamic transition in proteins remains unclear.…”

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confidence: 99%

Observation of fragile-to-strong dynamic crossover in protein hydration water

Chen

Liu

Fratini

et al. 2006

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

418

554

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At low temperatures, proteins exist in a glassy state, a state that has no conformational flexibility and shows no biological functions. In a hydrated protein, at temperatures տ220 K, this flexibility is restored, and the protein is able to sample more conformational substates, thus becoming biologically functional. This ''dynamical'' transition of protein is believed to be triggered by its strong coupling with the hydration water, which also shows a similar dynamic transition. Here we demonstrate experimentally that this sudden switch in dynamic behavior of the hydration water on lysozyme occurs precisely at 220 K and can be described as a fragile-to-strong dynamic crossover. At the fragile-to-strong dynamic crossover, the structure of hydration water makes a transition from predominantly high-density (more fluid state) to lowdensity (less fluid state) forms derived from the existence of the second critical point at an elevated pressure.glass transition ͉ liquid-liquid transition ͉ protein dynamics ͉ quasi-elastic neutron scattering W ithout water, a biological system would not function.Dehydrated enzymes are not active, but a single layer of water surrounding them restores their activity. It has been shown that the enzymatic activity of proteins depends crucially on the presence of at least a minimum amount of solvent water (1, 2). It is believed that Ϸ0.3 g of water per g of protein is sufficient to cover most of the protein surface with one single layer of water molecules and to fully activate the protein functionality. Thus, biological functions (3) such as enzyme catalysis can only be understood with a precise knowledge of the behavior of this single layer of water and how that water affects conformation and dynamics of the protein. The knowledge of the structure and dynamics of water molecules in the so-called hydration layer surrounding proteins is therefore of utmost relevance to the understanding of the protein functionality. It is well documented that at low temperatures proteins exist in a glassy state (4, 5), which is a solid-like structure without conformational flexibility. As the temperature is increased, the atomic motional amplitude increases linearly initially, as in a harmonic solid. In hydrated proteins, at Ϸ220 K, the rate of the amplitude increase suddenly becomes enhanced, signaling the onset of additional anharmonic and liquid-like motion (6-9). This ''dynamical'' transition of proteins is believed to be triggered by their strong coupling with the hydration water through the hydrogen bonding. The reasoning is derived from the finding that the protein hydration water shows some kind of dynamic transition at a similar temperature (10, 11). Here we demonstrate, through a high-resolution quasielastic neutron scattering (QENS) experiment, that this dynamic transition of hydration water on lysozyme protein is in fact the fragile-to-strong dynamic crossover (FSC) at 220 K, similar to that recently observed in confined water in cylindrical nanopores of silica materials (12, 13). Computer simulat...

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Heme-Solvent Coupling: A Mössbauer Study of Myoglobin in Sucrose

Cited by 84 publications

References 45 publications

Temperature-dependent macromolecular X-ray crystallography

Temperature-dependent macromolecular X-ray crystallography

The protein glass transition as measured by dielectric spectroscopy and differential scanning calorimetry

Observation of fragile-to-strong dynamic crossover in protein hydration water

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