Journal of the American Chemical Society, Vol.132, No.3, 1032-1040, 2010
High-Resolution Solid-State NMR Structure of a 17.6 kDa Protein
The use of pseudocontact shifts arising from paramagnetic metal ions in a microcrystalline protein sample is proposed as a strategy to obtain unambiguous signal assignments in solid-state NMR spectra enabling distance extraction for protein structure calculation. With this strategy, 777 unambiguous (281 sequential, 217 medium-range, and 279 long-range) distance restraints could be obtained from PDSD, DARR, CHHC, and the recently introduced PAR and PAIN-CP solid-state experiments for the cobalt(II)substituted catalytic domain of matrix metalloproteinase 12 (159 amino acids, 17.6 kDa). The obtained structure is a high resolution one, with backbone rmsd of 1.0 +/- 0.2 angstrom, and is in good agreement with the X-ray structure (rmsd to X-ray 1.3 angstrom). The proposed strategy, which may be generalized for nonmetalloproteins with the use of paramagnetic tags, represents a significant step ahead in protein structure determination using solid-state NMR.