Protein hydration and glass transitions

Gregory, Roger B.

doi:10.1007/978-1-4613-0311-4_4

Cited by 16 publications

(15 citation statements)

References 103 publications

(137 reference statements)

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“…We therefore conclude that the core is not in a glassy state. Fully hydrated proteins undergo a broad intramolecular dynamical transition to a glass-like state but only at low temperatures (180-220 K) (50). A similar transition is observed near room temperature for protein powders (50) but only at water contents (Ϸ0.1 h) much lower than in the core (Ϸ0.6 h).…”

Section: Discussionmentioning

confidence: 66%

“…Moreover, for Bacillus spores, heat resistance decreases exponentially with increasing core water content in the range 28-57% (17). Core dehydration might improve heat resistance by stabilizing proteins against thermal denaturation (50,53), presumably by disfavoring the unfolded state entropically (by excluding extended polypeptide conformations) as well as energetically (by restricting availability of water molecules for replacing intraprotein hydrogen bonds). However, to raise the heat denaturation temperature by 40°C in binary systems requires dehydration to Ϸ0.1 h, whereas little or no stabilization is seen at the hydration level (0.6 h) of the spore core (50,53).…”

Section: Discussionmentioning

confidence: 99%

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The physical state of water in bacterial spores

Sunde

Setlow

Hederstedt

et al. 2009

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

153

155

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The bacterial spore, the hardiest known life form, can survive in a metabolically dormant state for many years and can withstand high temperatures, radiation, and toxic chemicals. The molecular basis of spore dormancy and resistance is not understood, but the physical state of water in the different spore compartments is thought to play a key role. To characterize this water in situ, we recorded the water 2 H and 17 O spin relaxation rates in D2O-exchanged Bacillus subtilis spores over a wide frequency range. The data indicate high water mobility throughout the spore, comparable with binary proteinwater systems at similar hydration levels. Even in the dense core, the average water rotational correlation time is only 50 ps. Spore dormancy therefore cannot be explained by glass-like quenching of molecular diffusion but may be linked to dehydration-induced conformational changes in key enzymes. The data demonstrate that most spore proteins are rotationally immobilized, which may contribute to heat resistance by preventing heat-denatured proteins from aggregating irreversibly. We also find that the water permeability of the inner membrane is at least 2 orders of magnitude lower than for model membranes, consistent with the reported high degree of lipid immobilization in this membrane and with its proposed role in spore resistance to chemicals that damage DNA. The quantitative results reported here on water mobility and transport provide important clues about the mechanism of spore dormancy and resistance, with relevance to food preservation, disease prevention, and astrobiology.Bacillus subtilis ͉ hydration ͉ magnetic relaxation dispersion ͉ spore dormancy ͉ spore resistance

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Section: Discussionmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

The physical state of water in bacterial spores

Sunde

Setlow

Hederstedt

et al. 2009

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

153

155

View full text Add to dashboard Cite

show abstract

“…However, a variety of techniques have been employed to study the effect of hydration on thermal stability, internal protein dynamics, and function throughout a range of hydration levels. 145,166,174,214 -230 Much of this material has been extensively covered in an earlier review by Rupley and Careri 231 and more recently by Gregory, 232 therefore, in this section we will limit our discussion to those results that are most fundamental to understanding the hydration dependence to T d , in particular the question of whether the transition is due to the bulk solvent, the bound water, the protein alone or some combination. Full protein hydration, which is the amount considered enough to form a ''monolayer'' of coverage, occurs near 0.4h (g water/g protein) at typically 2-3 ordered waters per residue.…”

Section: Local Dynamics In Globular Proteinsmentioning

confidence: 98%

Thermodynamic and dynamic factors involved in the stability of native protein structure in amorphous solids in relation to levels of hydration

Hill

Shalaev

Zografi

2005

Journal of Pharmaceutical Sciences

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“…[24,25,22] This indicates that the dynamic transition of biomolecules at low temperatures is governed by hydration water.…”

mentioning

confidence: 96%

Which Properties of a Spanning Network of Hydration Water Enable Biological Functions?

Brovchenko¹,

Oleinikova²

2008

ChemPhysChem

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The central role of water in biological functions is well-recognized, but numerous questions concerning the physical mechanisms behind the importance of water for life remain unanswered. Water in biosystems exists mainly as hydration water. Analysis of the phase diagram of hydration water shows that biological functions are possible only when the surfaces of biomolecules are covered by spanning hydrogen-bonded networks of hydration water. The comparative studies of the various properties of hydrated biosystems in the presence and in the absence of a spanning water network should clarify its specific physical properties, which are crucial for biological functions. Herein, we summarize the recent progress in these studies. The biological activity of the living organisms is maximal in a narrow temperature interval, where the spanning network of hydration water breaks up with heating via a percolation transition. The entropy of the hydration water related to the diversity of cluster size diverges at this percolation threshold. The possible role of this phenomenon in life processes is discussed.

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Protein hydration and glass transitions

Cited by 16 publications

References 103 publications

The physical state of water in bacterial spores

The physical state of water in bacterial spores

Thermodynamic and dynamic factors involved in the stability of native protein structure in amorphous solids in relation to levels of hydration

Which Properties of a Spanning Network of Hydration Water Enable Biological Functions?

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