Please use this identifier to cite or link to this item: http://hdl.handle.net/20.500.12779/6152
Title: Bathochromic shift in Green Fluorescent Protein: A puzzle for QM/MM approaches
Authors: Filippi, Claudia
Buda, Francesco
Guidoni, Leonardo
Sinicropi, Adalgisa 
Issue Date: 2012
Project: None 
Journal: JOURNAL OF CHEMICAL THEORY AND COMPUTATION
Abstract: 
We present an extensive investigation of the vertical excitations of the anionic and neutral forms of wild-type green fluorescent protein using time-dependent density functional theory (TDDFT), multiconfigurational perturbation theory (CASPT2), and quantum Monte Carlo (QMC) methods within a quantum mechanics/molecular mechanics (QM/MM) scheme. The protein models are constructed via room-temperature QM/MM molecular dynamics simulations based on DFT and are representative of an average configuration of the chromophore protein complex. We thoroughly verify the reliability of our structures through simulations with an extended QM region, different nonpolarizable force fields, as well as partial reoptimization with the CASPT2 approach. When computing the excitations, we find that wave function as well as density functional theory methods with long-range corrected functionals agree in the gas phase with the extrapolation of solution experiments but fail in reproducing the bathochromic shift in the protein, which should be particularly significant in the neutral case. In particular, while all methods correctly predict a shift in the absorption between the anionic and neutral forms of the protein, the location of the theoretical absorption maxima is significantly blue-shifted and too close to the gas-phase values. These results point to either an intrinsic limitation of nonpolarizable force-field embedding in the computation of the excitations or to the need to explore alternative protonation states of amino acids in the close vicinity of the chomophore.
Description: 
40052
URI: http://hdl.handle.net/20.500.12779/6152
ISSN: 1549-9618
DOI: 10.1021/ct200704k
Appears in Collections:Publications

Show full item record

Page view(s)

2
Last Week
0
Last month
2
checked on May 9, 2021

Google ScholarTM

Check

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.