The treatment of errors in the isomorphous replacement method

✍ Scribed by Blow, D. M. ;Crick, F. H. C.

• Book ID: 114517789
• Publisher: International Union of Crystallography
• Year: 1959
• Tongue: English
• Weight: 962 KB
• Volume: 12
• Category: Article
• ISSN: 0365-110X
• DOI: 10.1107/s0365110x59002274

✦ Synopsis

This treatment is intended for complex structures where conventional refinement is impossible. A method is described for assessing the errors which arise in applying the isomorphous replacement method. Both errors due to non-isomorphism and observational errors are considered. Probability functions are derived which give, in the centrosymrnetric case, the probability of a correct sign determination, and in the non-centrosymmetric case the relative probabilities of different phases. These probabilities may be used to calculate a 'best' Fourier, in which the errors in electron density are minimized, and also to estimate the r.m.s, error in this 'best' Fourier.