X-ray structure of chromium(III)-containing transferrin: First structure of a physiological Cr(III)-binding protein
Document Type
Article
Publication Date
9-1-2020
Abstract
Transferrin, the Fe(III) transport protein in the blood, has been suggested to also serve as a Cr(III) transporter and as part of a Cr(III) detoxification system; however, the structure of the metal-binding sites has never been fully elucidated with bound Cr(III). Chromium(III)-transferrin was crystallized in the presence of the synergistic anion malonate. In the crystals, the proteins exists with a closed C-terminal lobe containing a Cr(III) and an open, unoccupied N-terminal lobe. The overall structure and the metal ion environments are extremely similar to those of Fe(III)- and Ti(IV)-containing transferrin crystallized under comparable conditions. The octahedral coordination about the Cr(III) is comprised of four ligands provided by the protein (two tyrosine residues, a histidine residue, and an aspartate residue) and a chelating malonate anion. This represents the first crystal structure of a Cr(III)-containing protein that binds Cr(III) as part of its physiological function.
Publication Source (Journal or Book title)
Journal of Inorganic Biochemistry
Recommended Citation
Petersen, C., Edwards, K., Gilbert, N., Vincent, J., & Thompson, M. (2020). X-ray structure of chromium(III)-containing transferrin: First structure of a physiological Cr(III)-binding protein. Journal of Inorganic Biochemistry, 210 https://doi.org/10.1016/j.jinorgbio.2020.111101