Extended Data Fig. 6: Alpha subunit domain structure and residue numbering.

Structures colored by domain for A) MarD, B) NifD, and C) DPOR ChlN. D) NifD secondary structure and E) enumeration of secondary structure based off Kim et al, 1992, Nature25. For MarD, cream highlighted cells indicate regions of poor resolution in Cryo-EM structure (Extended Data Fig. 5) and are inferred from AlphaFold 3 model.