This project was possible thanks to the great team formed with my shared co-first authors @sophia-pa.bsky.social and @rnfr2d2.bsky.social and the supervision of @schullerjm.bsky.social plus awesome contributions, specially from @stripplab.bsky.social @georghochberg.bsky.social and Silvan Scheller.

Amazingly, our phylogenetic reconstructions traced the origin of these clusters and their protein scaffolds in methanogens before being repurposed for nitrogen fixation.

Last but not least, three iron-sulfur clusters shape an electron transfer pathway towards the exposed coenzyme F430. Unexpectedly, these clusters are reminiscent of the [8Fe-9S-C] cofactors (or L-clusters) that so far had only been found in the nitrogenase family.

These changes allow CoB-SH to descend and form the heterodisulfide by-product with CoM. Whereas the more distal active site is still rigid while holding the substrates.