Why are Vibrational Lines Narrow in Proteins?

Daniel R. Martin, Dmitry V. Matyushov

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


The vibrational Stark effect in proteins yields line shifts indicative of strong internal electric fields up to a few volts per angstrom. These values are supported by numerical simulations of proteins. The simulations also show a significant breadth of field fluctuations translating to inhomogeneous broadening of vibrational lines. According to fluctuation-dissipation arguments, strong internal fields should lead to broad lines. Experimentally reported vibrational lines in proteins are, however, very narrow. This disconnect is explained here in terms of the insufficient (nonergodic) sampling of the protein's configurations on the lifetime of the vibrational probe. The slow component of the electric field fluctuations in proteins relaxes on the time scale of tens of nanoseconds and is dynamically frozen on the vibrational lifetime.

Original languageEnglish (US)
Pages (from-to)5932-5937
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number15
StatePublished - Aug 6 2020

ASJC Scopus subject areas

  • General Materials Science
  • Physical and Theoretical Chemistry


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