Ultrafast MAS Solid-State NMR Permits Extensive 13C and 1H Detection in Paramagnetic Metalloproteins

We show here that by combining tailored approaches based on ultrafast (60 kHz) MAS on the Co-II-replaced catalytic domain of matrix metalloproteinase 12 (CoMMP-12) we can observe and assign, in a highly paramagnetic protein in the solid state, C-13 and even H-1 resonances from the residues coordinating the metal center. In addition, by exploiting the enhanced relaxation caused by the paramagnetic center, and the low power irradiation enabled by the fast MAS, this can be achieved in remarkably short times and at very high field (21.2 T), with only less than 1 mg of sample. Furthermore, using the known crystal structure of the compound, we are able to distinguish and measure pseudocontact (PCS) contributions to the shifts up to the coordinating ligands and to unveil structural information.