Ergodicity breaking of iron displacement in heme proteins

Salman Seyedi, Dmitry Matyushov

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We present a model of the dynamical transition of atomic displacements in proteins. Increased mean-square displacement at higher temperatures is caused by the softening of the force constant for atomic/molecular displacements by electrostatic and van der Waals forces from the protein-water thermal bath. Displacement softening passes through a nonergodic dynamical transition when the relaxation time of the force-force correlation function enters, with increasing temperature, the instrumental observation window. Two crossover temperatures are identified. The lower crossover, presently connected to the glass transition, is related to the dynamical unfreezing of rotations of water molecules within nanodomains polarized by charged surface residues of the protein. The higher crossover temperature, usually assigned to the dynamical transition, marks the onset of water translations. All crossovers are ergodicity breaking transitions depending on the corresponding observation windows. Allowing stretched exponential relaxation of the protein-water thermal bath significantly improves the theory-experiment agreement when applied to solid protein samples studied by Mössbauer spectroscopy.

Original languageEnglish (US)
Pages (from-to)8188-8201
Number of pages14
JournalSoft Matter
Volume13
Issue number44
DOIs
StatePublished - Jan 1 2017

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Hemeproteins
Iron
proteins
crossovers
iron
Water
Proteins
softening
water
baths
Temperature
Van der Waals forces
Relaxation time
temperature
Glass transition
Electrostatics
relaxation time
Spectroscopy
electrostatics
Molecules

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics

Cite this

Ergodicity breaking of iron displacement in heme proteins. / Seyedi, Salman; Matyushov, Dmitry.

In: Soft Matter, Vol. 13, No. 44, 01.01.2017, p. 8188-8201.

Research output: Contribution to journalArticle

Seyedi, Salman ; Matyushov, Dmitry. / Ergodicity breaking of iron displacement in heme proteins. In: Soft Matter. 2017 ; Vol. 13, No. 44. pp. 8188-8201.
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