Effect of the point mutation H54N on the ferroxidase process of Rana catesbeiana H' ferritin.

Effect of the point mutation H54N on the ferroxidase process of Rana catesbeiana H' ferritin. J Inorg Biochem. 2019 May 07;197:110697 Authors: Pozzi C, Di Pisa F, Lalli D, Rosa C, Turano P, Mangani S Abstract Human H and Rana catesbeiana H' subunits in vertebrate ferritin protein cages catalyze the Fe(II) oxidation by molecular oxygen and promote the ferric oxide biomineral synthesis. By depositing iron biomineral, ferritins also prevent potentially toxic reactions products from Fe(II)-based Fenton chemistry. Recent work from our laboratory was aimed to describe the iron pathways within ferritin, from entrance into the cage to the ferroxidase site, and to understand the role played by amino-acid residues in iron trafficking and catalysis. Our approach exploits anomalous X-ray diffraction from ferritin crystals, exposed to a ferrous salt, to track transient iron binding sites along the path towards a well-defined di-iron site where they get oxidized by oxygen. Coupling structure determination with solution kinetic measurements on selected variants, allows validating the role played by key residues on the catalytic iron oxidation. Our previous studies on H' ferritin indicated the regulatory role played by His54, and by its human counterpart Gln58, on guiding Fe(II) ions to the catalytic site. Here, we have investigated the effects induced by substituting the wild type His54 with Asn54, having different iron coordination properties. We ...
Source: Journal of Inorganic Biochemistry - Category: Biochemistry Authors: Tags: J Inorg Biochem Source Type: research