Structure-based sequence alignment. The sequences of hTrx1, hPdc, rPdc and hPDCL2 were obtained from the Swiss-Prot database (accession Nos. P10599, P20941, P20942 and Q8N4E4, respectively). The alignment region of each sequence is labelled at the N- and C-termini. The secondary structure of hTrx1 is shown at the top and that of the hPDCL2 Trx-fold domain is shown at the bottom. Alignments were performed using the programs MULTALIN (Corpet, 1988 ▶) and ESPript (Gouet et al., 2003 ▶). Conserved residues are marked in red. Conserved residues in the Trx-fold domain of rPdc that contact G protein are labelled with blue stars.