Details

Autor(en) / Beteiligte

• Hasegawa, Jun-ya
• Ise, Takehiko
• Fujimoto, Kazuhiro J
• Kikuchi, Akihiro
• Fukumura, Eiko
• Miyawaki, Atsushi
• Shiro, Yoshitsugu

Titel

Excited States of Fluorescent Proteins, mKO and DsRed: Chromophore−Protein Electrostatic Interaction Behind the Color Variations

Ist Teil von

• The journal of physical chemistry. B, 2010-03, Vol.114 (8), p.2971-2979

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2010

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The emitting states of green fluorescent protein (GFP), monomeric Kusabira orange (mKO), and Discosoma red (DsRed) were studied using QM/MM and SAC-CI methods. By comparing the electronic structures among the green-, orange-, and red-emitting states as well as their electrostatic and quantum mechanical interactions within the protein cavity, the basic mechanisms for determining emission colors have been clarified. We found that the orange and red emissions of mKO and DsRed, respectively, result from cancellation between two effects, the π skeleton extension (red shift) and protein electrostatic potential (blue shift). The extension of the π skeleton enhances the intramolecular charge-transfer character of the transition, which makes the fluorescence energy more sensitive to the protein’s electrostatic potential. On the basis of this mechanism, we predicted amino acid mutations that could red shift the emission energy of DsRed. A novel single amino acid mutation, which was examined computationally, reduced the DsRed emission energy from 2.14 (579 nm) to 1.95 eV (636 nm), which is approaching near-infrared fluorescence.