Fig. 1. Comparison of the amino acid sequences corresponding to ahFAD2B and ahFAD2A. The top line is the most active fad2 sequence, ahFAD2B. The second line is ahFAD2A. The conserved histidine regions, putative binding sites for diiron (Shanklin et al., 1994) are in italics. The four unmatched amino acids are underlined. Amino acid 150 (numbered at right), adjacent to the second histidine-rich region, (bold) was mutagenized