Handling Twinning in Macromolecular Crystallography - Notes from the 2009
Toronto Workshop

 
WK.02 Handling Twinning in Macromolecular Crystallography

Saturday, July 25, 2009 – ACA Annual Meeting in Toronto, Canada

George Sheldrick, Garib Murshudov, Peter Zwart, Presiding

Twinning is a frequent problem in macromolecular crystallography that can easily be misunderstood and even lead to panic reactions. The aim of this workshop is to provide an understanding of twinning in a macromolecular context, and to show how one can often obtain entirely satisfactory and publishable structures despite twinning. Although small molecule crystallographers routinely determine twinned structures, this workshop is particularly timely because the latest versions of REFMAC and PHENIX_REFINE now include facilities for refining twinned structures of macromolecules.

• Introduction to twinning - Regine Herbst-Irmer
• Handling twinned data with the PHENIX package – Peter Zwart
• Twinning, worse twinning, and things worse than twinning – Todd Yeates
• Processing non-merohedral twins and refinement with SHELX – George M. Sheldrick
• Twinning in REFMAC – Garib N. Murshudov
• Twins and the phase problem – Zbigniew Dauter
• Non-merohedral twinning – Regine Herbst-Irmer