Generalized X-ray and neutron crystallographic analysis: more accurate and complete structures for biological macromolecules

Acta Crystallogr D Biol Crystallogr. 2009 Jun;65(Pt 6):567-73. doi: 10.1107/S0907444909011548. Epub 2009 May 15.


X-ray and neutron crystallographic techniques provide complementary information on the structure and function of biological macromolecules. X-ray and neutron (XN) crystallographic data have been combined in a joint structure-refinement procedure that has been developed using recent advances in modern computational methodologies, including cross-validated maximum-likelihood target functions with gradient-based optimization and simulated annealing. The XN approach for complete (including hydrogen) macromolecular structure analysis provides more accurate and complete structures, as demonstrated for diisopropyl fluorophosphatase, photoactive yellow protein and human aldose reductase. Furthermore, this method has several practical advantages, including the easier determination of the orientation of water molecules, hydroxyl groups and some amino-acid side chains.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Proteins / chemistry*
  • Computational Biology
  • Crystallography, X-Ray / methods*
  • Escherichia coli*
  • Feasibility Studies
  • Macromolecular Substances / chemistry*
  • Models, Theoretical
  • Neutron Diffraction / methods*
  • Phosphoric Triester Hydrolases / chemistry*
  • Photoreceptors, Microbial / chemistry*
  • Protein Conformation
  • Reproducibility of Results
  • Temperature


  • Bacterial Proteins
  • Macromolecular Substances
  • Photoreceptors, Microbial
  • photoactive yellow protein, Bacteria
  • Phosphoric Triester Hydrolases
  • diisopropyl-fluorophosphatase