How Sensitive is the Amide I Vibration of the Polypeptide Backbone to Electric Fields?

ABSTRACT: Site-selective isotopic labeling of amide carbonyls offers a nonperturbative means to introduce a localized infrared probe into proteins. Although this strategy has been widely used to investigate various biological questions, the dependence of the underlying amide I vibrational frequency on electric fields (or Stark tuning rate) has not been fully determined, which prevents it from being used in a quantitative manner in certain applications. Herein, through the use of experiments and molecular dynamics simulations, the Stark tuning rate of the amide I vibration of an isotopically labeled backbone carbonyl in a transmembrane α-helix is determined to be approximately 1.4 cm(-1) /(MV/cm). This result provides a quantitative basis for using this vibrational model to assess local electric fiel

SUBMITTER: Oh KI 

PROVIDER: S-EPMC4715676 | biostudies-literature | 2015 Dec

REPOSITORIES: biostudies-literature