Electron transfer pathways along the L- and M-branches in PbRC from Blastochloris viridis. The PbRC is composed of the L (red), M (blue), H (gold), and C (yellow) subunits. [PLPM]: BChlb pair; BL and BM: accessory BChlb; HL and HM: BPheob; QA: primary quinone (menaquinone); Fe: non-heme Fe complex.

Em profiles along the L- and M-branches in the XFEL structures for dataset a. (a) 0 ps. (b) 5 ps. (c) 300 ps.

Em profiles along the L- and M-branches in the XFEL structures for dataset b. (a) 0 ps. (b) 1 ps. (c) 5 ps. (d) 20 ps. (e) 300 ps. (f) 8 μs.

Contributions of the L/M residue pairs that are responsible for Em(BL) > Em(BM) (more than 10 mV) in the dark-state structure (mV). Difference: [contribution of subunit L to Em(BL)] + [contribution of subunit M to Em(BL)] – [contribution of subunit L to Em(BM)] – [contribution of subunit M to Em(BM)].

Contributions of the L/M residue pairs that are responsible for Em(HL) > Em(HM) (more than 10 mV) in the dark-state structure (mV). Difference: [contribution of subunit L to Em(HL)] + [contribution of subunit M to Em(HL)] – [contribution of subunit L to Em(HM)] – [contribution of subunit M to Em(HM)].

Residue pairs that are responsible for Em(BL) > Em(BM).

Time-dependent Em changes for BChlb and BPheob in the XFEL structures. (a) Dataset a. (b) Dataset b. ΔEm denotes the Em shift with respect to the dark state structure. Black solid lines: PL; black dotted lines: PM; blue solid lines BL; blue dotted lines: BM; red solid lines: HL; red dotted lines: HM.

Residues that shift Em(HL) most significantly during putative electron transfer in the XFEL structures (dataset a) (mV). The same residues are highlighted in the same colors for clarity.

Residues that shift Em(HL) most significantly during putative electron transfer in the XFEL structures (dataset b) (mV). The same residues are highlighted in the same colors for clarity.

Time-dependent changes in the lowest frequency out-of-plane modes of the chlorin rings in the XFEL structures (dataset a). Sad: saddling (red); ruf: ruffling (blue); dom: doming (green); wav(x, y): waving (x, y) (gray, dark blue); pro: propellering (orange). Solid and dotted lines indicate L and M branches, respectively. See Table S2 for the absolute values in the dark state for dataset a.

Time-dependent changes in the lowest frequency out-of-plane modes of the chlorin rings in the XFEL structures (dataset b). Sad: saddling (red); ruf: ruffling (blue); dom: doming (green); wav(x, y): waving (x, y) (gray, dark blue); pro: propellering (orange). Solid and dotted lines indicate L and M branches, respectively. See Table S3 for the absolute values in the dark state for dataset b.

Induced out-of-plane distortion of HL and HM in the PbRC protein environment of the dark structure for dataset a in response to the reduction (Å).

Induced out-of-plane distortion of HL and HM in the PbRC protein environment of the dark structure for dataset b in response to the reduction (Å).

Time-dependent Em changes for QA in the XFEL structures. (a) Dataset a. (b) Dataset b. ΔEm denotes the Em shift with respect to the dark state structure. Note that the calculated Em(QA) values for dataset a and dataset b in the dark structure are –223 mV and –209 mV, respectively, which are comparable to experimentally measured values of –150 mV for PbRC from Blastochloris viridis (menaquinone) 29 and –180 mV for PbRC from Rhodobacter sphaeroides (ubiquinone) 30.