FIGURE 10.

Partial sequence alignment of NqrB and flavodoxin. Amino acid sequences of flavodoxin from D. vulgaris (P00323) and Methanosarcina acetivorans (Q8TMF9) in the regions of the flavin-binding loops were aligned with the corresponding region of NqrB from C. pneumoniae (Q9Z8B6) and V. cholerae (A6XUU9). Residues of flavodoxin that mediate side-chain contact to riboflavin, including the two aromatic residues of flavodoxin, which stack to the isoalloxazine ring, are marked by arrows. Thr-236 of NqrB, which carries the covalently linked FMN, is indicated by an asterisk. Black bar, proposed transmembrane helix; gray bar, hydrophobic stretch.