Coacervation of alpha-elastin studied by ultrafast nonlinear infrared spectroscopy

Year: 2016

Authors: Ragnoni E., Palombo F., Green E., Winlove CP., Di Donato M., Lapini A.

Autors Affiliation: European Lab Nonlinear Spectroscopies, LENS, Via Nello Carrara 1, I-50019 Florence, Italy; Univ Siegen, Dept Phys, Walter Flex Str 3, D-57068 Siegen, Germany; Univ Exeter, Sch Phys & Astron, Exeter EX4 4QJ, Devon, England; Univ Florence, Dept Chem, Via Lastruccia 3-13, I-50019 Florence, Italy; Natl Inst Opt, INO, Largo Enrico Fermi 6, I-50125 Florence, Italy.

Abstract: Elastin is the main protein to confer elasticity to biological tissues, through the formation of a hierarchical network of fibres. a-Elastin, a soluble form of the protein, is widely used in studies of the biosynthesis of human elastic tissue and exhibits coacervation in solution. This process involves the association of alpha-elastin molecules through a liquid-liquid phase transition, which is reversible unless the temperature is driven sufficiently high to induce the formation of insoluble aggregates. The thermodynamics of this process have attracted interest over many years and in the present work we used ultrafast nonlinear infrared spectroscopy of the amide I protein backbone vibration to resolve the secondary structural changes occurring during coacervation and probe the protein dynamics on a picosecond time scale. Four classes of carbonyl oscillators with distinct absorption peaks were revealed and, through narrowband excitation, vibrational and anisotropy decays could be distinguished. Analysis of the vibrational lifetimes and anisotropy decay times of these bands characterized the conformational changes and revealed the structural bases of the coacervation process.

Journal/Review: PHYSICAL CHEMISTRY CHEMICAL PHYSICS

Volume: 18 (40)      Pages from: 27981  to: 27990

More Information: The authors would like to thank Prof. Maurizio Becucci at the Department of Chemistry, University of Firenze for his help in the acquisition of the light microscope images. The research leading to these results has received funding from LASERLAB-EUROPE (grant agreement no. 284464, EC’s Seventh Framework Programme).
KeyWords: Vibrational Spectroscopy; Human Tropoelastin; Proteins; Transition; Peptide; Inverse; Helix; Water; Dsc; D2o
DOI: 10.1039/c6cp04049g

ImpactFactor: 4.123
Citations: 7
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