Structural locations of envelope (E) protein epitope-specific knock-out substitutions.

<p>(A) Crystal structure of the DENV-2 E protein dimer <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004991#pone.0004991-Modis1" target="_blank">[15]</a> as it appears from above in mature virions and depicted as a ribbon diagram. The structural domains are colored red (EDI), yellow (EDII), and blue (EDIII). The highly conserved fusion peptide, located at the distal end of EDII is colored green and the glycans in EDI (N153) and EDII (N67) are depicted as ball and stick representation and colored brown. Epitope specific knock-out substitutions in the fusion peptide and in EDIII are depicted as space filling representations. (B) Side view of the same representation of the E protein dimer in mature virions with all structural depictions and colors the same as in panel A. (C) An enlarged view from panel B of the interface between the EDII fusion peptide of one E monomer and EDIII of the alternate monomer of the E dimer. EDII fusion peptide (EDII_FP), EDIII cross-reactive (EDIII_CR), and EDIII DENV-2 serotype specific (EDIII_TS) antigenic regions are noted and encircled. Residues locations of epitope-specific knock out substitutions utilized in this study are depicted as ball and stick representations. Substitutions of Gly106 and Leu107 in the EDII fusion peptide knock out the binding of broadly cross-reactive immunoglobulins, those recognizing viruses in the DENV complex and other flavivirus complexes. Substitutions of Lys310, Glu311, Pro364, and Lys388 in EDIII knock out the binding of immunoglobulins recognizing all or subsets of the four serotypes of DENV, but do not interfere with DENV-2 specific immunoglobulin recognition. Substitutions of Lys305 knock out the binding of DENV-2 serotype specific MAbs.