Although they utilize different approaches, Spectroscopy, X-Ray Crystallography and nuclear magnetic resonance NMR comprise the two-best means of analysing protein structure and function at or near atomic resolution. The degree to which these techniques differ and complement each has been a source of long-standing debate. Do proteins amenable to structural analysis by NMR also crystallize well? Does crystallography provide better structural resolution? In analysing NMR dynamics experiments, for example, one can greatly benefit from existing crystal structure data onto which the NMR structural data can be superimposed. Similarly, NMR structure data can be used to supplement a crystal structure with more information on the protein's dynamics, binding information, and conformational changes in solution. Because a protein that can be analysed by NMR is not necessarily amenable to crystallization (and vice-versa), the two techniques, either alone or in conjunction with one another, serve as two of the top complementary methods for protein structure determination.
