Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Chemistry and Pharmacology
The shake-and-bake procedure, which is based on the minimal function, has been tested and shown to be extremely effective in molecular-fragment recycling applications. Correctly positioned fragments as small as 5% of the scattering power of the structure typically have a 50% chance of producing a solution in a single recycling trial. While starting models for tangent-formula recycling methods normally require an average r.m.s. displacement error of less than −0.25 Å from the refined structure to ensure an adequate chance of success, the shake-and-bake method often tolerates r.m.s, model errors well in excess of 0.5 Å. Tests indicate that the new method can outperform traditional tangent-formula procedures in difficult structural applications involving multiple copies of pseudosymmetrically related molecules or low-resolution data.
Type of Medium: