Fig. 1.

Arrangement of the FMN and the FeS clusters in T. thermophilus complex I (5, 6). The clusters are named according to their nuclearity (2Fe or 4Fe), their subunit location (using the nomenclature for E. coli complex I, Table 1), and, when necessary, as ligated by four Cys (C) or three Cys and one His (H). The 4Fe[G]* cluster is not conserved in all species. Important edge-to-edge distances are indicated (Å), and the most likely electron transfer pathway is denoted by solid lines.