A procedure for joint refinement of macromolecular structures with X-ray and neutron diffraction data from single crystals

A procedure is presented for the stereochemically restrained least-squares refinement of macromolecular structures with neutron and X-ray diffraction data from single crystals. This procedure has been tested by refining a model of ribonuclease A using neutron data to minimal spacings of 2.8 Å and X-ray data from within 2.0 Å spacings. Joint X-ray and neutron refinement is well conditioned and tends to avoid false minima that may occur when a medium-resolution structure is refined solely with the neutron structure factors.