Temperature dependence of dielectric relaxations in α-elastin coacervate: Evidence for a peptide librational mode

Urry, Dan W.; Henze, R.; Redington, Patrick; Long, Marcus J. C.; Prasad, K. U.

doi:10.1016/0006-291x(85)90146-9

Cited by 17 publications

(2 citation statements)

References 25 publications

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“…The temperatures for the α-elastin data on the left edge of the curves listed as (a)-(m) are 68, 12.5, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65 and 70°C, respectively. This demonstrates that the same relaxation occurs in a fragment of the natural elastic fibre as has been so thoroughly characterized in the model elastic protein, poly(GVGVP). Reproduced, with permission, from Urry et al (1985a). (b) The imaginary (absorptive) part of the dielectric permittivity of natural fibrous elastin showing an increasing relaxation at ca.…”

Section: (B) the Acoustic Absorption Experiments (I) Sample Preparation And Experimental Set-upmentioning

confidence: 99%

Elastin: a representative ideal protein elastomer

Urry

Hugel

Seitz

et al. 2002

Phil. Trans. R. Soc. Lond. B

288

255

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During the last half century, identification of an ideal (predominantly entropic) protein elastomer was generally thought to require that the ideal protein elastomer be a random chain network. Here, we report two new sets of data and review previous data. The first set of new data utilizes atomic force microscopy to report single-chain force-extension curves for (GVGVP) 251 and (GVGIP) 260 , and provides evidence for single-chain ideal elasticity. The second class of new data provides a direct contrast between lowfrequency sound absorption (0.1-10 kHz) exhibited by random-chain network elastomers and by elastin protein-based polymers.Earlier composition, dielectric relaxation (1-1000 MHz), thermoelasticity, molecular mechanics and dynamics calculations and thermodynamic and statistical mechanical analyses are presented, that combine with the new data to contrast with random-chain network rubbers and to detail the presence of regular non-random structural elements of the elastin-based systems that lose entropic elastomeric force upon thermal denaturation.The data and analyses affirm an earlier contrary argument that components of elastin, the elastic protein of the mammalian elastic fibre, and purified elastin fibre itself contain dynamic, non-random, regularly repeating structures that exhibit dominantly entropic elasticity by means of a damping of internal chain dynamics on extension.

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Section: (B) the Acoustic Absorption Experiments (I) Sample Preparation And Experimental Set-upmentioning

confidence: 99%

Elastin: a representative ideal protein elastomer

Urry

Hugel

Seitz

et al. 2002

Phil. Trans. R. Soc. Lond. B

288

255

View full text Add to dashboard Cite

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“…In order of increasing relaxation frequency, the three main relaxations are generally associated with protein tumbling (frequency f < 10 MHz, relaxation time τ > 15 ns), to hydration water in the interfacial region surrounding the biomolecule ( τ in the 20 ps–10 ns range) and to the orientational polarisation of the free water molecules ( f > 10 GHz, τ < 15 ps), respectively) (Kaatze, 1997; Cametti et al, 2011). Dielectric studies on concentrated solutions of polypentapeptide analogues of elastin (Buchet et al, 1988; Urry et al, 1997), an elastin coacervate (Urry et al, 1985), or fibrous elastin (Bone and Pethig, 1985; Urry et al, 2002) highlighted both the low-frequency dielectric dispersion due to a librational mode of the protein/polypeptide and the high-frequency dispersion due to water. This latter dispersion was found to be a composite dispersion (Urry et al, 1997) due to at least three kinds of water: free water, water hydrogen bonded to the polar groups of the polypeptide backbone and clathrate-like water associated with the hydrophobic side chains.…”

Section: The Elastin/water Systemmentioning

confidence: 99%

Structural and physical basis for the elasticity of elastin

Depenveiller,

Baud,

Belloy

et al. 2024

Quart. Rev. Biophys.

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Elastin function is to endow vertebrate tissues with elasticity so that they can adapt to local mechanical constraints. The hydrophobicity and insolubility of the mature elastin polymer have hampered studies of its molecular organisation and structure-elasticity relationships. Nevertheless, a growing number of studies from a broad range of disciplines have provided invaluable insights, and several structural models of elastin have been proposed. However, many questions remain regarding how the primary sequence of elastin (and the soluble precursor tropoelastin) governs the molecular structure, its organisation into a polymeric network, and the mechanical properties of the resulting material. The elasticity of elastin is known to be largely entropic in origin, a property that is understood to arise from both its disordered molecular structure and its hydrophobic character. Despite a high degree of hydrophobicity, elastin does not form compact, water-excluding domains and remains highly disordered. However, elastin contains both stable and labile secondary structure elements. Current models of elastin structure and function are drawn from data collected on tropoelastin and on elastin-like peptides (ELPs) but at the tissue level, elasticity is only achieved after polymerisation of the mature elastin. In tissues, the reticulation of tropoelastin chains in water defines the polymer elastin that bears elasticity. Similarly, ELPs require polymerisation to become elastic. There is considerable interest in elastin especially in the biomaterials and cosmetic fields where ELPs are widely used. This review aims to provide an up-to-date survey of/perspective on current knowledge about the interplay between elastin structure, solvation, and entropic elasticity.

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Dielectric relaxation studies on bovine ligamentum nuchae

1988

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SynopsisDielectric relaxation studies of bovine ligamentum nuchae are reported over the frequency range of 1 MHz to 1 GHz and over the temperature range of 2348°C. A temperature-dependent relaxation process was obsewed at low megahertz-frequency with the correlation time of around 40 ns. The result is quite similar to that of a synthetic polypentapeptide (WGVG) and of a-elastin. T h e relaxation is proposed to arise in part from the peptide libration within the polypentapeptide of bovine ligamentum nuchae.

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Temperature dependence of dielectric relaxations in α-elastin coacervate: Evidence for a peptide librational mode

Cited by 17 publications

References 25 publications

Elastin: a representative ideal protein elastomer

Elastin: a representative ideal protein elastomer

Structural and physical basis for the elasticity of elastin

Dielectric relaxation studies on bovine ligamentum nuchae

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