Light driven ultrafast electron transfer in oxidative redding of Green Fluorescent Proteins

Sci Rep. 2013;3:1580. doi: 10.1038/srep01580.

Abstract

Fluorescent proteins undergoing green to red (G/R) photoconversion have proved to be potential tools for investigating dynamic processes in living cells and for photo-localization nanoscopy. However, the photochemical reaction during light induced G/R photoconversion of fluorescent proteins remains unclear. Here we report the direct observation of ultrafast time-resolved electron transfer (ET) during the photoexcitation of the fluorescent proteins EGFP and mEos2 in presence of electron acceptor, p-benzoquinone (BQ). Our results show that in the excited state, the neutral EGFP chromophore accepts electrons from an anionic electron donor, Glu222, and G/R photoconversion is facilitated by ET to nearby electron acceptors. By contrast, mEos2 fails to produce the red emitting state in the presence of BQ; ET depletes the excited state configuration en route to the red-emitting fluorophore. These results show that ultrafast ET plays a pivotal role in multiple photoconversion mechanisms and provide a method to modulate the G/R photoconversion process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzoquinones / chemistry*
  • Benzoquinones / radiation effects
  • Electron Transport / radiation effects
  • Green Fluorescent Proteins / chemistry*
  • Green Fluorescent Proteins / radiation effects*
  • Light*
  • Oxidation-Reduction / radiation effects

Substances

  • Benzoquinones
  • Green Fluorescent Proteins
  • quinone