Dynamics in natural and designed elastins and their relation to elastic fiber structure and recoil

Carvajal, Ma. Faye Charmagne A.; Preston, John; Jamhawi, Nour; Sabo, T. Michael; Bhattacharya, Shibani; Aramini, James M.; Wittebort, Richard J.; Koder, Ronald L.

doi:10.1016/j.bpj.2021.06.043

Cited by 4 publications

(8 citation statements)

References 62 publications

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“…Furthermore, increasing helix–helix interactions can enhance formation of fractal networks of mature coacervates ( 49 ). While the presence of hydrophobic termini has been shown to stabilize the helical structure of the cross-linking domains ( 29 ), our NMR experiments show no additional changes in secondary structure resulting from modulating the lengths of these domains ( SI Appendix , Fig. S9 ), suggesting an alternate mechanism underlying the observed maturation.…”

Section: Discussionmentioning

confidence: 60%

“…5 ), which underscores the significance of the length of the hydrophobic domains at the termini to this maturation process, could explain these differences. Indeed, previous NMR studies of our construct demonstrated the stabilization of α -helical structure in the cross-linking domains when flanked between hydrophobic domains ( 29 ). This characteristic secondary structure is lacking in the absence of flanking hydrophobic domains, which can act as helical end caps that promote structure ( 46 ).…”

Section: Discussionmentioning

confidence: 73%

“…In order to gain insight into the nature of the condensed phase of elastin coacervates, we use here a model minielastin protein that contains alternating hydrophobic and cross-linking domains that mimic the domain structure of full-length tropoelastin, construct 20′20′-24′-24′24′, herein referred to simply as minielastin ( Fig. 1 A and B ) ( 28 , 29 ). In this model protein, the quasirepeats of tropoelastin exons 20 and 24 are replaced by absolute repeats (20′ and 24′) for simplification, the cross-linking domains are composed of fused exons 21 and 23 as in previous works ( 12 ), and the termini are capped with a second respective hydrophobic domain in order to better model the full-length protein, which is flanked by expanded hydrophobic domains ( 28 ) ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…NMR experiments were done as previously described ( 29 ). Briefly, protein was lyophilized and diluted to 200 μM in buffer containing 45 mM phosphate buffer, pH 6.0.…”

Section: Methodsmentioning

confidence: 99%

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Liquid to solid transition of elastin condensates

Ceballos

Preston

Vairamon

et al. 2022

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

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Liquid–liquid phase separation of tropoelastin has long been considered to be an important early step in the complex process of elastin fiber assembly in the body and has inspired the development of elastin-like peptides with a wide range of industrial and biomedical applications. Despite decades of study, the material state of the condensed liquid phase of elastin and its subsequent maturation remain poorly understood. Here, using a model minielastin that mimics the alternating domain structure of full-length tropoelastin, we examine the elastin liquid phase. We combine differential interference contrast (DIC), fluorescence, and scanning electron microscopy with particle-tracking microrheology to resolve the material transition occurring within elastin liquids over time in the absence of exogenous cross-linking. We find that this transition is accompanied by an intermediate stage marked by the coexistence of insoluble solid and dynamic liquid phases giving rise to significant spatial heterogeneities in material properties. We further demonstrate that varying the length of the terminal hydrophobic domains of minielastins can tune the maturation process. This work not only resolves an important step in the hierarchical assembly process of elastogenesis but further contributes mechanistic insight into the diverse repertoire of protein condensate maturation pathways with emerging importance across biology.

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Section: Discussionmentioning

confidence: 60%

Section: Discussionmentioning

confidence: 73%

Section: Resultsmentioning

confidence: 99%

“…NMR experiments were done as previously described ( 29 ). Briefly, protein was lyophilized and diluted to 200 μM in buffer containing 45 mM phosphate buffer, pH 6.0.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Liquid to solid transition of elastin condensates

Ceballos

Preston

Vairamon

et al. 2022

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

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“…Although the sequences of hydrophobic amino acids prevent the formation of large secondary structures, the dynamics of the hydrated backbone of the elastin molecule results in transient hydrogen-bonded turns, which form highly disordered, but not random, assemblies of dynamic conformations such as short and labile beta structures and polyproline II helices [ 31 , 37 ]. Both molecular dynamics simulations of elastin-like peptides sequences [ 30 , 32 ] and solid-state NMR experiments with mature elastin [ 36 , 106 ] reveal the extremely dynamic nature of hydrophobic domains providing high entropy of elastin in the relaxed state ( Figure 1 , left side). Rausches and Pomes [ 32 ], based on massive-scale molecular dynamics simulations, describe the assembly of elastin individual chains in water as a maximally disordered, melt-like state—a liquid state of elastin.…”

Section: Elasticity Of Soft Tissuesmentioning

confidence: 99%

Mechanical Properties and Functions of Elastin: An Overview

Trębacz

Barzycka

2023

Biomolecules

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Human tissues must be elastic, much like other materials that work under continuous loads without losing functionality. The elasticity of tissues is provided by elastin, a unique protein of the extracellular matrix (ECM) of mammals. Its function is to endow soft tissues with low stiffness, high and fully reversible extensibility, and efficient elastic–energy storage. Depending on the mechanical functions, the amount and distribution of elastin-rich elastic fibers vary between and within tissues and organs. The article presents a concise overview of the mechanical properties of elastin and its role in the elasticity of soft tissues. Both the occurrence of elastin and the relationship between its spatial arrangement and mechanical functions in a given tissue or organ are overviewed. As elastin in tissues occurs only in the form of elastic fibers, the current state of knowledge about their mechanical characteristics, as well as certain aspects of degradation of these fibers and their mechanical performance, is presented. The overview also outlines the latest understanding of the molecular basis of unique physical characteristics of elastin and, in particular, the origin of the driving force of elastic recoil after stretching.

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Elastin recoil is driven by the hydrophobic effect

Jamhawi,

Koder,

Wittebort

2024

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

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Elastin is an extracellular matrix material found in all vertebrates. Its reversible elasticity, robustness, and low stiffness are essential for the function of arteries, lungs, and skin. It is among the most resilient elastic materials known: During a human lifetime, arterial elastin undergoes in excess of 2 × 10 9 stretching/contracting cycles without replacement, and slow oxidative hardening has been identified as a limiting factor on human lifespan. For over 50 y, the mechanism of entropic recoil has been controversial. Herein, we report a combined NMR and thermomechanical study that establishes the hydrophobic effect as the primary driver of elastin function. Water ordering at the solvent:protein interface was observed as a function of stretch using double quantum 2 H NMR, and the most extensive thermodynamic analysis performed to date was obtained by measuring elastin length and volume as a function of force and temperature in normal water, heavy water and with cosolvents. When stretched, elastin’s heat capacity increases, water is ordered proportional to the degree of stretching, the internal energy decreases, and heat is released in excess of the work performed. These properties show that recoil in elastin under physiological conditions is primarily driven by the hydrophobic effect rather than by configurational entropy as is the case for rubber. Consistent with this conclusion are decreases in the thermodynamic signatures when cosolvents that alter the hydrophobic effect are introduced. We propose that hydrophobic effect-driven recoil, as opposed to a configurational entropy mechanism where hardening from crystallization can occur, is the origin of elastin’s unusual resilience.

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Dynamics in natural and designed elastins and their relation to elastic fiber structure and recoil

Cited by 4 publications

References 62 publications

Liquid to solid transition of elastin condensates

Liquid to solid transition of elastin condensates

Mechanical Properties and Functions of Elastin: An Overview

Elastin recoil is driven by the hydrophobic effect

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