Concentric Helical Wheel Projections of Proposed Lassa and Ebola Helices. Helical wheel projections are shown for 18 amino acid segments of the proposed helices of Lassa and Ebola viruses. The projections are arranged concentrically to align the viral sequences, with the inner sequence that from Lassa virus, and the outer sequence from Ebola. Zaire virus (Genbank U31033). Rectangles indicate identical or highly similar residues in each sequence. Heavy lines indicate the hemicylinder of charge exclusion (hydrophobic) subtending an angle of 160° in each alignment. Below each wheel projection the linear sequences are also aligned to show the identities (solid lines) and high similarities (dotted lines). A. Concentric alignment of the amino terminal amphipathic helices ("lower amphi") of Lassa (amino acids 309-326, in wheel positions 1-18 respectively) and Ebola (555-572). B. Concentric alignment of the charged, pre-insertion helices ("CPI Helix") of Lassa (398-415) and Ebola (618-635).