Figure 1. Alignment of cytochrome b₅ reductase and cytochromes b₅a and b₅b protein sequences for zebrafish, human, and rat.

A; alignment of CYB5R3 sequences (Uniprot accession codes: zebrafish, Q6NYE6; human P00387; rat, P20070). Initial portions in italics indicate the missing residues in the soluble isoform (CYB5R3–2) of the mammalian proteins and the homologous residues in zebrafish protein; the first amino acid in the recombinant protein used in this work and the initial amino acid in the mammalian isoform 2 are marked in bold and yellow background. B; alignment of CYB5a (microsomal CYB5) and CYB5b (outer membrane CYB5) sequences (Uniprot accession codes: zebrafish b₅a, Q7T341; human b₅a, P00167; rat b₅a, P00173; zebrafish b₅b, Q6NY41; human b₅b, O43169; rat b₅b, P04166). Conserved heme-binding histidines are indicated in blue background. Amino acids in italics indicate sequences removed in the N-termini of CYB5b and the membrane binding C-terminal regions of CYB5a and CYB5b. The putative membrane intercalating helix region is shown in a rectangle. The first and last amino acids in the recombinant proteins used in this work, along with the splicing sites for the soluble isoform of mammalian cytochrome b₅a proteins are marked in bold and yellow background; the first and last amino acids in the recombinant proteins used in other works^{25, 26} are indicated in bold with green background.