De novo determination of peptide structure with solid-state magic-angle spinning NMR spectroscopy

The three-dimensional structure of the chemotactic peptide N-formyl-L-Met-L-Leu-L-Phe-OH was determined by using solid-state NMR (SSNMR). The set of SSNMR data consisted of 16 C-13-N-15 distances and 18 torsion angle constraints (on 10 angles), recorded from uniformly C-13,N-15- and N-15-labeled samples. The peptide's structure was calculated by means of simulated annealing and a newly developed protocol that ensures that all of conformational space, consistent with the structural constraints, is searched completely. The result is a high-quality structure of a molecule that has thus far not been amenable to single-crystal diffraction studies. The extensions of the SSNMR techniques and computational methods to larger systems appear promising.