1. Center for Biological Sequence Analysis, Biocentrum-DTU, Technical University of Denmark, Building 208, DK-2800 Lyngby, Denmark, Department of Medicinal Chemistry, The Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark, and Division of Biocomputing, Department of Biochemistry and Molecular Biology, University of New Mexico School of Medicine, MSC11 6145, Albuquerque, New Mexico 87131