1. Department of Chemistry, University College London, 20 Gordon Street, London, WC1H OAJ, U.K., Biological NMR Centre, Department of Biochemistry, Henry Wellcome Building, University of Leicester, University Road, Leicester LE1 9HN, U.K., Department of Biochemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QG, U.K., and School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, and Department of Biochemistry, School of Medical Sciences, University Walk, Bristol BS8...