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A Spotlight on the Compatibility between XFEL and Ab Initio Structures of the Oxygen Evolving Complex in Photosystem II
Author(s) -
Narzi Daniele,
Mattioli Giuseppe,
Bovi Daniele,
Guidoni Leonardo
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201700722
Subject(s) - photosystem ii , femtosecond , ab initio , oxygen evolving complex , cluster (spacecraft) , chemistry , oxygen evolution , diffraction , chemical physics , ab initio quantum chemistry methods , electron , crystallography , atomic physics , photosynthesis , physics , molecular physics , molecule , laser , optics , nuclear physics , computer science , biochemistry , organic chemistry , electrode , electrochemistry , programming language
Abstract The Mn 4 CaO 5 cluster of photosystem II promotes a crucial step in the oxygenic photosynthesis, namely, the water‐splitting reaction. The structure of such cluster in the S 1 state of the Kok–Joliot's cycle has been recently resolved by femtosecond X‐ray free‐electron laser (XFEL) measurements. However, the XFEL results are characterized by appreciable discrepancies with previous X‐ray diffraction (XRD), as well as with S 1 models based on ab initio calculations. We provide here a unifying picture based on a combined set of DFT‐based structures and molecular dynamics simulations of the S 0 and S 1 states. Our findings indicate that the XFEL results cannot be interpreted on the grounds of a single structure. A combination of two S 1 stable isomers together with a minority contribution of the S 0 state is necessary to reproduce XFEL results within 0.16 Å.