Room temperature XFEL crystallography reveals asymmetry in the vicinity of the two phylloquinones in photosystem I.

ABSTRACT: Photosystem I (PS I) has a symmetric structure with two highly similar branches of pigments at the center that are involved in electron transfer, but shows very different efficiency along the two branches. We have determined the structure of cyanobacterial PS I at room temperature (RT) using femtosecond X-ray pulses from an X-ray free electron laser (XFEL) that shows a clear expansion of the entire protein complex in the direction of the membrane plane, when compared to previous cryogenic structures. This trend was observed by complementary datasets taken at multiple XFEL beamlines. In the RT structure of PS I, we also observe conformational differences between the two branches in the reaction center around the secondary electron acceptors A_1A and A_1B. The π-stacked P

SUBMITTER: Keable SM 

PROVIDER: S-EPMC8575901 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature