MAGICSQUASH: ITERATIVE MULTIPLE DOMAIN AND MULTIPLE SPACE GROUP NCS AVERAGING. David J. Schuller, Department of Molecular Biology, University of California, Irvine, CA, 92697-3900 USA.

The simultaneous application of multiple constraints such as non-crystallographic symmetry (NCS) averaging, solvent levelling, histogram matching and Sayre's equation has proven to be very effective for phase refinement and extension. An existing program, SQUASH, exists for carrying this out in a fast, automated and iterative manner [1]. Modifications have been made to this program to allow the averaging of multiple domain and multiple space group NCS while retaining the ease of use and automation, resulting in program MAGICSQUASH [2]. The averaging algorithms of MAGICSQUASH are described, and examples ofstructures solved with MAGICSQUASH are described, including some with multiple domain or multiple space group NCS.

[1] K.D. Cowtan & P. Main (1993) Acta Crystallogr. D49, 148-157.

[2] D.J. Schuller (1996) Acta Crystallogr. D. in press.