title: A multivariate likelihood SIRAS function for phasing and model refinement.
abstract: A likelihood function based on the multivariate probability distribution of all observed structure-factor amplitudes from a single isomorphous replacement with anomalous scattering experiment has been derived and implemented for use in substructure refinement and phasing as well as macromolecular model refinement. Efficient calculation of a multidimensional integration required for function evaluation has been achieved by approximations based on the function's properties. The use of the function in both phasing and protein model building with iterative refinement was essential for successful automated model building in the test cases presented.
authors.affiliation: Biophysical Structural Chemistry, Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands. p.skubak@chem.leidenuniv.nl
authors.forename: Pavol
authors.initials: P
authors.lastname: Skubák
authors.forename: Garib
authors.initials: G
authors.lastname: Murshudov
authors.forename: Navraj S
authors.initials: NS
authors.lastname: Pannu
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry; D000818:Animals; D017122:Bacteriophage T4 / Q000201:enzymology; D018360:Crystallography, X-Ray / Q000379:methods*; D030562:Databases, Protein; D016013:Likelihood Functions; D008780:Methyltransferases / Q000737:chemistry; D008958:Models, Molecular; D011506:Proteins / Q000737:chemistry*; D013295:Streptococcus mutans / Q000201:enzymology
chemical_list: D011506:Proteins; D008780:Methyltransferases; D000251:Adenosine Triphosphatases