The epitope binding site is conserved between 4E10 and its GEPs.

<p>(<b>A</b>) Residues from the combining sites of 4E10 and GEPs, superimposed based on bound-state structures, contacting the NWFDIT core epitope (shown in a cartoon representation as a grey corkscrew) are shown in a stereo view. 4E10 and GEP residues are shown in licorice stick representation and colored as follows: 4E10 Fv (3LH2.pdb, in complex with ES T88) in purple, 4E10 Fab (2FX7.pdb, in complex with an extended 16-mer NWFDIT-containing peptide) in orange, GEP 1 in yellow, GEP 2 in cyan, and GEP 7 in red. Analyses and depictions were restricted to the core epitope to maximize comparability. Calculated SA buried in the complexes and Sc between core epitope and Ab are: 4E10 Fab/epitope peptide: SA = 355 Ų, Sc = 0.78; 4E10/T88: SA = 367 Ų, Sc = 0.77; GEP 1/T117: SA = 342 Ų, Sc = 0.69; GEP 2/T117: SA = 305 Ų, Sc = 0.74; GEP 7/T117: SA = 343 Ų, Sc = 0.66. (<b>B</b>) The NWFDIT core epitope is shown in a licorice stick representation isolated from the superimposed complex structures, highlighting the high degree of conservation of both the position and conformation of the peptide across 4E10 and GEP complexes.