Application of distance geometry to the proton assignment problem.

Assignment of the hydrogen spectrum is the first step in the conventional procedure for the determination of molecular structure by 1H-nmr. In this paper, we explore the possibility of directly exploiting the distances derived from nuclear Overhauser effect experiments to generate a three-dimensional structure that is then assigned based on knowledge of the connectivity or primary sequence. This effort is analogous to that of the protein crystallographers in tracing electron density of the peptide chain. In particular, we compare structures produced by distance geometry to known peptide secondary structures to see what level of information is required to "trace" the backbone alpha-carbon and amide hydrogens and the beta-carbon hydrogens. We conclude that this approach is only useful with excellent quality stereo-resolved data.