Fig 5.

Diagram of the nitrogen fixation operon in Leptospirillum group IV UBA BS, L. ferrodiazotrophum, and L. ferrooxidans. NifX-assoc, NifX-associated protein; Fdx, ferredoxin; [FeS], FeS cluster assembly protein. Gaps (brackets) in the Leptospirillum group IV UBA BS operon correspond to genes: (i) genes encoding two hypothetical (Hypo) proteins, nifS, aminotransferase gene; and (ii) nifU, nifT, genes encoding two hypothetical proteins, ferredoxin gene, nifW, and genes encoding two final nitrogen regulatory proteins P-II. aa, amino acids.