Structure-based alignment of <i>Pa</i>PabC and <i>Lp</i>PabC.

<p>Residues encased in black are strictly conserved. Red stars indicate the tyrosine residues at Position I (<i>Pa</i>PabC Y92) and Position II (<i>Lp</i>PabC Y144). Triangles mark residues that are discussed in the text. Red triangles identify Lys140 and residues that interact directly with the Lys140-PLP adduct; yellow triangles mark residues that contribute to the organization of the active site or that participate in solvent mediated interactions between the protein and the cofactor.