Where Do 3D Protein Structure Data Come From?
  1. Accurate: 88% by X-ray crystallography, 11% by NMR, and 0.5% by electron microscopy*.

  2. Rough: Comparative modeling, but templates available for only ~20% of domains.

  3. Ab initio theory does not predict tertiary structure accurately enough for most purposes.

  4. Details ...

by Eric Martz, University of Massachusetts, October 2004.