title: Characterizing the Structures, Spectra, and Energy Landscapes Involved in the Excited-State Proton Transfer Process of Red Fluorescent Protein LSSmKate1.
abstract: By applying molecular dynamics (MD) simulations and quantum chemical calculations, we have characterized the states and processes involved in the excited-state proton transfer (ESPT) of LSSmKate1. MD simulations identify two stable structures in the electronic ground state of LSSmKate1, one with a protonated chromophore and the other with a deprotonated chromophore, thus leading to two separate low-energy absorption maxima with a large energy spacing, as observed in the calculated and experimentally measured absorption spectra. Proton transfer is induced by electronic excitation. When LSSmKate1 is excited, the electrons in the chromophore are transferred from the phenol ring to the N-acylimine moiety; the acidity of a phenolic hydroxyl group is thus enhanced. The calculated potential energy curves (PECs) exhibit energetic feasibility in the generation of the fluorescent species in LSSmKate1, and the exact agreement between the calculated and experimentally measured values of the large Stokes shift further provides solid theoretical evidence for the ESPT process taking place in photoexcited LSSmKate1. The molecular environments play a significant role in the geometries and absorption/emission energies of the chromophores. Overall, TD-ωB97X-D/molecular mechanics (MM) provides a better description of the optical properties of LSSmKate1 than TD-B3LYP/MM, although it always overestimates the excitation energies.
authors: State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China.
authors: Fasheng
authors: F
authors: Chen
authors: State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China.
authors: Qiao
authors: Q
authors: Zeng
authors: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, China.
authors: Wei
authors: W
authors: Zhuang
authors: State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China.
authors: WanZhen
authors: W
authors: Liang
mesh_terms: D008164:Luminescent Proteins / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D011487:Protein Conformation; D011522:Protons; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence; D000097573:Red Fluorescent Protein
chemical_list: D008164:Luminescent Proteins; D011522:Protons; D000097573:Red Fluorescent Protein