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Structures of the Chromophore Binding Sites in BLUF Domains as Studied by Molecular Dynamics and Quantum Chemical Calculations †
Author(s) -
Obanayama Kazuya,
Kobayashi Hiroaki,
Fukushima Kentaro,
Sakurai Minoru
Publication year - 2008
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 - 10.1111/j.1751-1097.2008.00351.x
Subject(s) - chromophore , molecular dynamics , quantum chemical , chemistry , quantum chemistry , chemical physics , dynamics (music) , quantum , computational chemistry , crystallography , molecule , physics , photochemistry , quantum mechanics , crystal structure , organic chemistry , supramolecular chemistry , acoustics
BLUF (blue‐light sensing using FAD) domains constitute a new family of flavin‐based blue light photoreceptors. The photocycle of BLUF is unique in the sense that a few hydrogen bond rearrangements are accompanied by only slight structural changes in the bound chromophore. The hydrogen bond rearrangements upon illumination have been inferred from spectral changes in the chromophore: ∼10 nm redshift of the absorption maximum and ∼16 cm −1 downshift of the C4=O stretching frequency. However, the exact features of the hydrogen bond network around the active site are still the subject of some controversy. In particular, the orientation of a conserved Gln (Gln63 in AppA) is presently one of the most questioned topics in the field. Here we perform molecular dynamics simulations for the wild‐type AppA, AppA1‐124C20S, BlrB and T110078 and furthermore quantum chemical calculations to investigate their spectroscopic properties in the dark and signaling states. On the basis of these results, we reveal the dynamic aspect of hydrogen bonding networks at the active site and propose theoretically reasonable models for the dark and signaling states of the BLUF domains.