Table 2.3.8.1

Rossmann, M. G.; Arnold, E.

doi:10.1107/97809553602060000556

International
Tables for
Crystallography
Volume B
Reciprocal space
Edited by U. Shmueli

pdf | chapter contents | chapter index | related articles

International Tables for Crystallography (2006). Vol. B. ch. 2.3, p. 261

Table 2.3.8.1

M. G. Rossmann^a ^* and E. Arnold^b

^aDepartment of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA, and ^bCABM & Rutgers University, 679 Hoes Lane, Piscataway, New Jersey 08854-5638, USA
Correspondence e-mail: mgr@indiana.bio.purdue.edu

Table 2.3.8.1 | top | pdf |
Molecular replacement: phase refinement as an iterative process

(A)	$[{\bf F}_{\rm obs}, \alpha'_{n}, m'_{n} \rightarrow \rho_{n}]$
(B)	$[\rho_{n} \rightarrow \rho_{n}]$ (modified)
	(i) Use of noncrystallographic symmetry operators
	(ii) Definition of envelope limiting volume within which noncrystallographic symmetry is valid
	(iii) Adjustment of solvent density^†
	(iv) Use of crystallographic operators to reconstruct modified density into a complete cell
(C)	$[\rho_{n} \hbox{(modified)} \rightarrow {\bf F}_{{\rm calc}, \, n + 1}\hbox{; } \alpha_{{\rm calc}, \, n + 1}]$
(D)	$[({\bf F}_{{\rm calc}, \, n + 1}, \alpha_{{\rm calc}, \, n + 1}) + ({\bf F}_{\rm obs}, \alpha_{0}) \rightarrow {\bf F}_{\rm obs}, \alpha'_{n + 1}, m'_{n + 1}]$
	(i) Assessment of reliability of new phasing set $[\alpha_{n + 1}]$ in relation to original phasing set $[\alpha_{0}(w)]$
	(ii) Use of figures of merit $[m_{0}, m_{n + 1}]$ and reliability w to determine modified phasing set $[\alpha'_{n + 1}, m'_{n + 1}]$ ^‡
	(iii) Consideration of $[\alpha_{n + 1}]$ and $[m_{n + 1}]$ where there was no prior knowledge of
	(a) $[{\bf F}_{\rm obs}]$ (e.g. very low order reflections or uncollected data)
	(b) $[\alpha_{0}]$ (e.g. no isomorphous information or phase extension)
(E)	Return to step (A) with $[\alpha'_{n + 1}, m'_{n + 1}]$ and a possibly augmented set of $[{\bf F}_{\rm obs}]$ .