Download MendeleyThe Bacillus anthracis class Ib ribonucleotide reductase subunit NrdF intrinsically selects manganese over iron.
Grave, K., Griese, J.J., Berggren, G., Bennett, M.D., Hogbom, M.(2020) J Biol Inorg Chem 25: 571-582
- PubMed: 32296998
- DOI: https://doi.org/10.1007/s00775-020-01782-3
- Primary Citation of Related Structures:
6TQV, 6TQW, 6TQX, 6TQY, 6TQZ - PubMed Abstract:
Correct protein metallation in the complex mixture of the cell is a prerequisite for metalloprotein function. While some metals, such as Cu, are commonly chaperoned, specificity towards metals earlier in the Irving-Williams series is achieved through other means, the determinants of which are poorly understood. The dimetal carboxylate family of proteins provides an intriguing example, as different proteins, while sharing a common fold and the same 4-carboxylate 2-histidine coordination sphere, are known to require either a Fe/Fe, Mn/Fe or Mn/Mn cofactor for function. We previously showed that the R2lox proteins from this family spontaneously assemble the heterodinuclear Mn/Fe cofactor. Here we show that the class Ib ribonucleotide reductase R2 protein from Bacillus anthracis spontaneously assembles a Mn/Mn cofactor in vitro, under both aerobic and anoxic conditions, when the metal-free protein is subjected to incubation with Mn II and Fe II in equal concentrations. This observation provides an example of a protein scaffold intrinsically predisposed to defy the Irving-Williams series and supports the assumption that the Mn/Mn cofactor is the biologically relevant cofactor in vivo. Substitution of a second coordination sphere residue changes the spontaneous metallation of the protein to predominantly form a heterodinuclear Mn/Fe cofactor under aerobic conditions and a Mn/Mn metal center under anoxic conditions. Together, the results describe the intrinsic metal specificity of class Ib RNR and provide insight into control mechanisms for protein metallation.
Organizational Affiliation:
Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden.
