ct300706r_si_001.pdf (2.87 MB)
Computational Study of Absorption Spectra of the Photoconvertible Fluorescent Protein EosFP in Different Protonation States
journal contribution
posted on 2012-11-13, 00:00 authored by Petra ImhofAbsorption spectra of the green-to-red convertible fluorescent
protein EosFP have been computed in a hybrid quantum mechanical/molecular
mechanical (QM/MM) framework. The experimentally observed absorption
maximum at ∼390 nm is well reproduced by the protein with a
neutral chromophore, and the anionic form is computed to absorb close
to the experimentally determined maximum at ∼500 nm. Absorption
of a zwitterionic form is calculated to lie in the same spectral region;
however, this species cannot be unambiguously assigned to the experimental
spectra. Variation of the protonation states of residues surrounding
the chromophore do not have significant impact on the positions of
the absorption maxima. In particular, protonation of Glu212 leaves
the calculated spectra largely unaffected. This is consistent with
the spectra of the E212Q mutant, which differ from the wild-type spectra
only in the intensities but not in the positions of the absorption
bands.