Laboratory of Macromolecular Crystallography

Programs for low resolution ab-initio macromolecular phasing

Ab-initio - it is supposed that generally, the only necessary experimental information is structure factors magnitudes Fobs(s) obtained in the conventional X-ray diffraction experiment with the native object.

Attention. In the present version it is supposed that ALL low resolution magnitudes (with the exception of the forbidden reflections) were measured and are present in the input file.

Low resolution - the goal of this stage of the structure study is to phase several dozens of reflection of the lowest resolution. The particular resolution edge depends on the unit cell dimensions.

Start phases - at advanced stages of phasing some information may appear on the preferable values of structure factor phases. This information is referenced as "start phases" and it is used when generating phase values. It may be absent on the first step of phasing.

References phases - this information may be absent at any step and it is never used in the phasing. When being present it is used to specify the preferable origin/enantiomorph for the "answer" output and allows to calculate some statistics. The phases obtained by some alternative method may be used as reference ones to make the comparison of the results more straightforward.

Program suits

  • GENMEM suite - the package designed for low resolution connectivity based ab-initio phasing.

     More about low resolution ab-initio phasing.

General publications

     The full texts of papers of LCM staff
  • Lunin, V.Y., Lunina, N.L., Petrova, T.E., Skovoroda, T.P., Urzhumtsev, A.G. & Podjarny, A.D. (2000). "Low-resolution ab initio phasing: problems and advances". Acta Cryst. D56, 1223-1232.

  • Lunin V.Y., Lunina N., Podjarny A., Bockmayr A. & Urzhumtsev A. "Ab initio phasing starting from low resolution". Z.Kristallogr. (2002). 217, 668-685.