Figure 4

S-LAP divergence at divalent cation binding and catalytic residues. Amino acid composition at the seven residues involved in metal ion binding and catalytic residues is displayed according to the S-LAP phylogeny presented in Figure 1. For cation binding sites, residues matching the M17 leucyl aminopeptidase consensus are highlighted in red, substitutions to other metal binding amino acids in M17 leucyl aminopeptidases are highlighted in pink and substitutions to non-M17 leucyl aminopeptidase metal binding residues in white. For catalytic residues, residues matching the M17 leucyl aminopeptidase consensus are highlighted in red and those divergent from the consensus in white. Amino acid residues Lys327, Asp332, Asp350 and Glu411 comprise the tight, Zn2+-specific binding (site 2), while residue 409 is involved in loose coordination of divalent cations (site 1).