title: On the ab initio solution of the phase problem or macromolecules at very low resolution. II. Generalized likelihood based approach to cluster discrimination.
abstract: The multisolution strategies for direct phasing at very low resolution, such as the few atoms model technique, result in a number of alternative phase sets, each of them arising from a cluster of closely related models. Use of a Monte-Carlo type computer procedure is suggested to choose between the possible phase sets. It consists of generating a large number of pseudo-atom models inside the mask defined by a trial phase set and the use of histograms of magnitude correlation to evaluate the masks. It is shown that the procedure may be considered as a generalization of the statistical maximum-likelihood principle and may be used as a powerful supplementary tool in the likelihood-based approaches to the phase problem solution.
authors.affiliation: Institute of Mathematical Problems of Biology, Russian Academy of Sciences, Pushchino, Moscow Region, 142292, Russia.
authors.forename: V Y
authors.initials: VY
authors.lastname: Lunin
authors.forename: N L
authors.initials: NL
authors.lastname: Lunina
authors.forename: T E
authors.initials: TE
authors.lastname: Petrova
authors.forename: A G
authors.initials: AG
authors.lastname: Urzhumtsev
authors.forename: A D
authors.initials: AD
authors.lastname: Podjarny
mesh_terms: D016000:Cluster Analysis; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D016013:Likelihood Functions; D008958:Models, Molecular; D009010:Monte Carlo Method