Schematic representation of the gp41 domains.

The flexibility of the MPER is revealed by the differences in its structure. (A) NMR spectroscopy structure of the MPER peptide (KWASLWNWFNITNWYIK) in DPC micelles. (Top) Side view with the exposed face oriented toward the top of the figure. (Bottom) End view. (Reprinted with permission from reference 209. Copyright © 2001 American Chemical Society.) (B) Crystal structure of the 2F5 epitope peptide (EKNEQELLELDKWASLW) (yellow) in complex with the 2F5 Fab (not shown). This figure was made using DeepView Swiss-PDB Viewer from PDB coordinates (PDB accession number 1TJI) described previously (170). (C) Crystal structure of Fab 4E10 in complex with its epitope peptide (GWNWFDITNWGK) (yellow). The light chain is shown in red, and the heavy chain is shown in blue. This figure was made using DeepView Swiss-PDB Viewer from PDB coordinates (PDB accession number 1TZG) described previously (38). (D) Hypothetical model of the MPER (DKWASLWNWFDITNWLW) as described by Nelson et al. (164). (Reprinted from reference 164 with permission.)