Fig. 3. Structural alignment of the thioredoxin family proteins investigated in this study. The structures of the various redoxins were pairwise aligned to the structure of E. coli Trx 1 (PDB code ; 1xob) using PyMOL and thereafter manually arranged in this alignment. The residues directly interacting in the E. c. Trx1–PAPS reductase complex were highlighted with a green background. The residues were also specified below the sequence, as well as the interacting residues in PAPS reductase and the parts of the amino acids involved in these interactions (bb: backbone, sc: side chain). The interactions were calculated with ‘contact’ of the CCP4 suite.58 Conserved residues were highlighted with a yellow, positively charged residues with a blue, and negatively charged residues with a red background. The positions of the active site as well as the Trx-fold specific cis-Pro residues were also marked above the sequences. The secondary structures of E. c. Grx1 was also included above the sequences, the secondary structure of E. c. Trx1 below the sequences.