TY  - JOUR
A1  - Goetze, Jan P.
A1  - Greco, Claudio
A1  - Mitric, Roland
A1  - Bonacic-Koutecky, Vlasta
A1  - Saalfrank, Peter
T1  - BLUF Hydrogen network dynamics and UV/Vis spectra: A combined molecular
 dynamics and quantum chemical study
JF  - JOURNAL OF COMPUTATIONAL CHEMISTRY
N2  - Blue light sensing using flavin (BLUF) protein photoreceptor domains change their hydrogen bond network after photoexcitation. To explore this phenomenon, BLUF domains from R. sphaeroides were simulated using Amber99 molecular dynamics (MD). Five starting configurations were considered, to study different BLUF proteins (AppA/BlrB), Trp conformations (Win/Wout), structure determination (X-ray/NMR), and finally, His protonation states. We found dependencies of the hydrogen bonds on almost all parameters. Our data show an especially strong correlation of the Trp position and hydrogen bonds involving Gln63. The latter is in some contradiction to earlier results (Obanayama et al., Photochem. Photobiol. 2008, 84 10031010). Possible origins and implications are discussed. Our calculations support conjectures that Gln63 is more flexible with Trp104 in Win position. Using snapshots from MD and time-dependent density functional theory, UV/vis spectra for the chromophore were determined, which account for molecular motion of the protein under ambient conditions. In accord with experiment, it is found that the UV/vis spectra of BLUF bound flavin are red-shifted and thermally broadened for all calculated p ? p* transitions, relative to gas phase flavin at T = 0 K. However, differences in the spectra between the various BLUF configurations cannot be resolved with the present approach. (c) 2012 Wiley Periodicals, Inc.
KW  - blue-light sensor
KW  - flavin
KW  - molecular dynamics
KW  - TD-DFT
KW  - BLUF domains
Y1  - 2012
U6  - https://doi.org/10.1002/jcc.23056
SN  - 0192-8651
VL  - 33
IS  - 28
SP  - 2233
EP  - 2242
PB  - WILEY-BLACKWELL
CY  - HOBOKEN
ER  -