Identification of Histidine-60 Interaction with Copper in Activation of Chironomidae Ferrochelartase

Site-directed mutagenesis study of the conserved residue in ferrochelatase of chironomidae showed the binding interaction of copper with histidine-60. The activities of the variants increase by > 4-fold with H60N and 2 fold with H60D. The study identifies for the first time that the highly conserved H60 is a key molecular determinant in directing a catalytically competent mode of metal binding in the active site.