Affiliation: | 1. MRC Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Francis Crick Avenue, Cambridge CB2 0QH, UK;2. University of Cambridge, Department of Medicine, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK;3. Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health Bethesda, MD 20892, USA |