Fig. 1: Structural dynamics in the QA–QB area during S1–S2–S3 transitions.
From: Oxygen-evolving photosystem II structures during S1–S2–S3 transitions
a,b, Structures of PSII in the QA–QB area are superposed with Fobs(1F) – Fobs(Dark) (a) and Fobs(2F) – Fobs(1F) (b) difference density maps contoured at +3.5σ (green) and −3.5 σ (orange) from 20 ns to 5 ms. Ground-state models (dark in a and 1F in b) are depicted in grey, and the D1 and D2 proteins in the intermediate structures are shown in yellow and cyan, respectively. Residues of D1 and D2 are depicted without and with underlines, respectively. Hydrogen bonds are shown by black dotted lines. Black solid lines link the cofactors in PSII and their ligands. Black arrows indicate structural changes based on the refined models. The ordered and disordered atoms (non-haem iron in this figure and water molecules in the other figures) in the intermediate structures are encircled by cyan- and red-dotted lines, respectively. These nomenclature, hydrogen bonds, ligands of cofactors and black arrows are used in the other figures, unless otherwise stated.
