Crystal Structure of Two Anti-Porphyrin Antibodies with Peroxidase Activity

摘要: We report the crystal structures at 2.05 and 2.45 A resolution of two antibodies, 13G10 14H7, directed against an iron(III)-αααβ-carboxyphenylporphyrin, which display some peroxidase activity. Although these antibodies differ by only one amino acid in their variable λ-light chain 86% sequence identity heavy chain, complementary determining regions (CDR) CDRH1 CDRH3 adopt very different conformations. The presence Met or Leu residues positions preceding residue H101 respectively, yields to shallow combining sites pockets with shapes that are mainly hydrophobic. hapten other carboxyphenyl-derivatized iron(III)-porphyrins have been modeled active both using protein ligand docking program GOLD. is maintained antibody 14H7 a strong network hydrogen bonds three carboxylates carboxyphenyl substituents porphyrin, as well numerous stacking van der Waals interactions hydrophobic CDRH3. However, no was found chelate iron. Modeling also allows us rationalize recognition alternative porphyrinic cofactors effect imidazole binding on activity 13G10/porphyrin complexes.