Five-component dielectric dispersion in bovine serum albumin solution

Essex, C G; Symonds, M. S.; Sheppard, R J; Grant, E H; Lamote, R.; Soetewey, F.; Rosseneu, Maryvonne; Peeters, H.

doi:10.1088/0031-9155/22/6/008

Cited by 39 publications

(26 citation statements)

References 20 publications

(13 reference statements)

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“…Grant (49) combined new data fo r bovine serum albumin with that of Buchanan et al (48) to show that the protein-bound water exhibited rotational relaxations over the range of a few MHz to several hundreds MHz, with the overall dielectric behavior possibly being infl uenced by rotations of protein polar sidegroups. Grant's observations were largely confi rmed by the later works of Pennock & Schwan (50) and Essex et al (51).…”

Section: Proteinsmentioning

confidence: 76%

Protein-Water Interactions Determined by Dielectric Methods

Pethig

1992

Annu. Rev. Phys. Chem.

296

254

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KEY WORDS: dipole moment, enzymic activity, hydration, hydrogen bonds, orientational relaxation time, proton percolation INTRODUCTIONIn one of the earliest reports of the physicochemical properties of a protein, Sorensen (1) asked "Does crystallised egg-albumin contain water?" Fol lowing a detailed compositional analysis, he found that such samples contain about 0.22 g water per g water-free egg-albumin. In later work, he gives the water content of crystallized hemoglobin as 0.35 gjg (2). We now know that protein molecules can have from 0.20 to 0.70 g strongly associated (bound) water per g protein, and through modern x-ray and neutron diffraction studies, we have for some proteins a detailed knowledge of the location and bonding of much of this water (3-5). By using the latest high-resolution NMR techniques, we can even identify individual molecules of hydration water and characterize their binding sites on the protein molecule (6). Thus, in general and as a convenient method of classification, two kinds of water molecules associated with proteins have been identified: internal water and peripheral water. The internal water molecules, which form an integral part of a protein structure, diminish local charge-charge inter actions and reduce destabilizing effects that arise from otherwise unbonded proton donors and acceptors (7,8). These molecules exchange with bulk water in time scales ranging from tens of seconds to months (9, 10). As a rough gauge of the upper limit of internal water, we can consider the small 177 0066-426Xj92jll01-0l77$ 02.00 Annu. Rev. Phys. Chem. 1992.43:177-205. Downloaded from www.annualreviews.org by University of Sydney on 09/17/13. For personal use only.Quick links to online content Further ANNUAL REVIEWS 178 PETHIG enzyme pancreatic trypsin inhibitor (mol wt 6700), which contains fo ur internal waters (8). As this represents a hydration content of 1.07 wt%, we can conclude that most of the water bound to proteins is associated with the protein surface. Such hydration shells of peripheral water do not freeze upon cooling (11). And, although distinct nonrandom distributions of water molecules occur at the polar side-chains, consistent with the expected stereochemistry of the potential hydrogen-bonding sites (5), there is no evidence fo r the existence of extensive ice-like fo rmations of water molecules around protein molecules. Klotz (12) proposed that water might form clathrate-type structures around hydrophobic groups at protein sur faces. Evidence for this is found for the small, hydrophobic plant protein crambin, in which a cluster of pentagonal arrays, made up of 16 hydrogen bonded water molecules, sits at a hydrophobic intermolecular cleft (13).Of the approximately 90 water molecules per crambin molecule, 73 have been located (14), and all of them contribute to an ordered hydrogen bonded network around the protein surface. From NMR studies (6, and references cited therein), it appears that protein hydration is more dis ordered in solution than has been indicated from single crystal...

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Section: Proteinsmentioning

confidence: 76%

Protein-Water Interactions Determined by Dielectric Methods

Pethig

1992

Annu. Rev. Phys. Chem.

296

254

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“…However, this point of view was later reconsidered. Current opinion assumes that the δ‐relaxation process cannot be solely attributed to the dynamics of bound water and that other processes, such as internal protein motions, contribute to this relaxation mode …”

Section: Resultsmentioning

confidence: 99%

Coupling between overall rotational diffusion and domain motions in proteins and its effect on dielectric spectra

Ryabov¹

2015

Proteins

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In this work, we formulate a closed-form solution of the model of a semirigid molecule for the case of fluctuating and reorienting molecular electric dipole moment. We illustrate with numeric calculations the impact of protein domain motions on dielectric spectra using the example of the 128 kDa protein dimer of Enzyme I. We demonstrate that the most drastic effect occurs for situations when the characteristic time of protein domain dynamics is comparable to the time of overall molecular rotational diffusion. We suggest that protein domain motions could be a possible explanation for the high-frequency contribution that accompanies the major relaxation dispersion peak in the dielectric spectra of protein aqueous solutions. We propose that the presented computational methodology could be used for the simultaneous analysis of dielectric spectroscopy and nuclear magnetic resonance data. Proteins 2015; 83:1571-1581. © 2015 Wiley Periodicals, Inc.

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“…[40] is shown, together with that of a suspension of phospholipid vesicles (radius 13.5 nm, volume fraction p = 0.14) [42]. The δ-dispersion is associated with the protein hydration sheath [41,44,45]. Positive DEP can be expected for both particle types in the frequency range where their relative permittivity, ε r , exceeds that (~78) of pure bulk water.…”

Section: The β-And δ-Dispersions Associated With Protein Hydrationmentioning

confidence: 95%

“…The designation of a particular Greek letter does not specify a specific physico-chemical mechanism responsible for that dispersion. Figure 5 shows the β-dispersion exhibited by solvated BSA [40,41], together with an aqueous suspension of phospholipid nano-vesicles [42].…”

Section: The β-And δ-Dispersions Associated With Protein Hydrationmentioning

confidence: 99%

Protein Dielectrophoresis: A Tale of Two Clausius-Mossottis—Or Something Else?

Pethig

2022

Micromachines

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Standard DEP theory, based on the Clausius–Mossotti (CM) factor derived from solving the boundary-value problem of macroscopic electrostatics, fails to describe the dielectrophoresis (DEP) data obtained for 22 different globular proteins over the past three decades. The calculated DEP force appears far too small to overcome the dispersive forces associated with Brownian motion. An empirical theory, employing the equivalent of a molecular version of the macroscopic CM-factor, predicts a protein’s DEP response from the magnitude of the dielectric β-dispersion produced by its relaxing permanent dipole moment. A new theory, supported by molecular dynamics simulations, replaces the macroscopic boundary-value problem with calculation of the cross-correlation between the protein and water dipoles of its hydration shell. The empirical and formal theory predicts a positive DEP response for protein molecules up to MHz frequencies, a result consistently reported by electrode-based (eDEP) experiments. However, insulator-based (iDEP) experiments have reported negative DEP responses. This could result from crystallization or aggregation of the proteins (for which standard DEP theory predicts negative DEP) or the dominating influences of electrothermal and other electrokinetic (some non-linear) forces now being considered in iDEP theory.

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Five-component dielectric dispersion in bovine serum albumin solution

Cited by 39 publications

References 20 publications

Protein-Water Interactions Determined by Dielectric Methods

Protein-Water Interactions Determined by Dielectric Methods

Coupling between overall rotational diffusion and domain motions in proteins and its effect on dielectric spectra

Protein Dielectrophoresis: A Tale of Two Clausius-Mossottis—Or Something Else?

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