Optimal alignment of PPOs from several plant
species. Accession nos.: apricot, no. AF020786; apple, no. P43309 (Boss
et al., 1995); grape, no. P43311 (Dry and Robinson, 1994); fava bean,
no. 418754 (Cary et al., 1992); Virginian pokeweed, no. D45385 (Joy et
al., 1995); tomato, no. Q08296 (Newmann et al., 1993). A dot refers to
identity with apricot. A space denotes a gap introduced for improved
alignment. Single underlined amino acid residues correspond to the
transit peptide. Domain I of transit peptide is marked by •. Domain
II of transit peptide is marked by ⋄. The “n-region” of domain II
of transit peptide is shaded in blue. The thylakoid transfer domain of
the domain II of transit peptide is shaded in green. Shown as bold
letters are the hydrophobic amino acids of thylakoid transfer domain
and the precleavage site. The first amino acid residue of the mature
protein is shaded in black. Double underlined amino acid residues
correspond to the sequence obtained from N-terminal sequencing of the
purified protein. Copper domains A and B of the mature protein are
shaded in yellow. His residues predicted to be copper-binding ligands
are boxed.