…nt addresses: Christine Ender, UCL Cancer Institute, Paul O’Gorman Building, 72 Huntley Street, London WC1E 6BT, UK. Gunter Meister, University of Regensburg, Biochemistry I, Universitätsstrasse 31, 93053 Regensburg, Germany. Received 2011 Sep 2; Accepted 2012 Mar 22; Issue date …