1. School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin D04 V1W8, Ireland
2. National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Bethesda, Maryland 20892, United States
3. Department of Biochemistry and Structural Biology, Lund University, Box 118, Lund 221 00, Sweden