Resonantly Enhanced Multiphoton Ionization Spectrum of the Neutral Green Fluorescent Protein Chromophore.
The photophysics of the green fluorescent protein is governed by the electronic structure of the chromophore at the heart of its β-barrel protein structure. We present the first two-color, resonance-enhanced, multiphoton ionization spectrum of the isolated neutral chromophore in vacuo with supporting electronic structure calculations. We find the absorption maximum to be 3.65 ± 0.05 eV (340 ± 5 nm), which is blue-shifted by 0.5 eV (55 nm) from the absorption maximum of the protein in its neutral form. Our results show that interactions between the chromophore and the protein have a significant influence on the electronic structure of the neutral chromophore during photoabsorption and provide a benchmark for the rational design of novel chromophores as fluorescent markers or photomanipulators.
†Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, United Kingdom.
Jason B
JB
Greenwood
†Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, United Kingdom.
Jordan
J
Miles
†Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, United Kingdom.
Simone De
SD
Camillis
†Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, United Kingdom.
Peter
P
Mulholland
‡Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom.
Lijuan
L
Zhang
‡Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom.
Michael A
MA
Parkes
‡Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom.
Helen C
HC
Hailes
‡Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom.
Helen H
HH
Fielding
absorption; femtosecond; gas phase; time-dependent density functional theory; ultraviolet