Affiliation: | (1) Department of Biochemistry, University of Cambridge, Tennis Court Road, CB2 1QW Cambridge, U.K.;(2) Cambridge Centre for Molecular Recognition, University of Cambridge, Tennis Court Road, CB2 1QW Cambridge, U.K.;(3) Present address: Department of Structural Biology, Biozentrum der Universität Basel, Klingelbergerstrasse 70, CH-4056 Basel, Switzerland |