FIG 1 .

Structure of reovirus attachment protein σ1. (A) Schematic of the HIV-1 gp41 ectodomain. The gp41 ectodomain is comprised of a fusion peptide (FP), N-terminal heptad repeat (NHR), C-terminal heptad repeat (CHR), and membrane-proximal external region (MPER) (8). The transmembrane region also is indicated. MPER-specific 2F5, 4E10, and Z13 MAb epitopes are indicated. N- and C-terminal boundaries are shown. Numbers represent amino acid positions. (B) A full-length depiction of σ1, generated by appending a predicted trimeric α-helical coiled coil to the amino terminus of the largest available crystallized σ1 fragment (30). The three monomers of the crystallized region are shown in red, blue, and yellow; the model is shown in gray. Tail, body, and head regions are indicated. N and C termini are shown. Insertion sites for 2F5 sequences are indicated in purple. Insertion sites for whole MPER sequences are indicated in green.