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Spectral Tuning of Photoactive Yellow Protein †
Author(s) -
Yamato T.,
Ishikura T.,
Kakitani T.,
Kawaguchi K.,
Watanabe H.
Publication year - 2007
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/2006-06-16-ra-930
Subject(s) - chromophore , excitation , ab initio , maxima and minima , chemistry , molecular orbital , molecular physics , chemical physics , ground state , molecular dynamics , molecule , absorption spectroscopy , electronic structure , atomic physics , computational chemistry , physics , photochemistry , optics , quantum mechanics , mathematical analysis , mathematics , organic chemistry
We report a theoretical study on the optical properties of a small, water‐soluble photosensory receptor, photoactive yellow protein (PYP). A hierarchical ab initio molecular orbital calculation accurately evaluated the optical absorption maximum of the wild‐type, as well as the λ max values of 12 mutants. Electronic excitation of the chromophore directly affects the electronic state of nearby atoms in the protein environment. This effect is explicitly considered in the present study. Furthermore, the spectral tuning mechanism of PYP was investigated at the atomic level. The static disorder of a protein molecule is intimately related to the complex nature of its energy landscape. By using molecular dynamics simulation and quantum mechanical structure optimization, we obtained multiple minimum energy conformations of PYP. The statistical distribution of electronic excitation energies of these minima was compared with the hole‐burning experiment (Masciangioli, T. [2000] Photochem. Photobiol . 72, 639), a direct observation of the distribution of excitation energies.