PELDOR was employed at high microwave frequencies to experimentally assess the homodimeric structure of the active mouse R2 ribonucleotide reductase protein in solution. We use the essential diferric cluster tyrosyl cofactor radicals as spin probes to detect their distance and mutual orientation and present a general approach to analyze the data. This work demonstrates for the first time the capability of this method to construct a biradical structure when the crystal structure is not available. This method has considerable potential for studying the assembly of protein complexes in which paramagnetic centers are rigidly embedded.
- Denysenkov VP, Biglino D, Lubitz W, Prisner TF, Bennati M. Structure of the tyrosyl biradical in mouse R2 ribonucleotide reductase from high-field PELDOR. Angew Chem Int Ed Engl.; 47:1224 (2008).