A estrutura líquida da elastina: mero acaso, fortuita necessidade ou design inteligente?

sábado, janeiro 13, 2018

The liquid structure of elastin

Sarah Rauscher, Régis Pomès

The Hospital for Sick Children, Canada University of Toronto, Canada

RESEARCH ARTICLE Nov 9, 2017

Peptide hydration in the liquid-like aggregate.

Abstract

The protein elastin imparts extensibility, elastic recoil, and resilience to tissues including arterial walls, skin, lung alveoli, and the uterus. Elastin and elastin-like peptides are hydrophobic, disordered, and undergo liquid-liquid phase separation upon self-assembly. Despite extensive study, the structure of elastin remains controversial. We use molecular dynamics simulations on a massive scale to elucidate the structural ensemble of aggregated elastin-like peptides. Consistent with the entropic nature of elastic recoil, the aggregated state is stabilized by the hydrophobic effect. However, self-assembly does not entail formation of a hydrophobic core. The polypeptide backbone forms transient, sparse hydrogen-bonded turns and remains significantly hydrated even as self-assembly triples the extent of non-polar side chain contacts. Individual chains in the assembly approach a maximally-disordered, melt-like state which may be called the liquid state of proteins. These findings resolve long-standing controversies regarding elastin structure and function and afford insight into the phase separation of disordered proteins.

https://doi.org/10.7554/eLife.26526.001

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