Structure-based design of a protein immunogen that displays an HIV-1 gp41 neutralizing epitope.

TitleStructure-based design of a protein immunogen that displays an HIV-1 gp41 neutralizing epitope.
Publication TypeJournal Article
Year of Publication2011
AuthorsStanfield RL, Julien J-P, Pejchal R, Gach JS, Zwick MB, Wilson IA
JournalJ Mol Biol
Date Published2011 Dec 2
KeywordsAmino Acid Sequence, Calorimetry, Crystallography, X-Ray, Epitopes, HIV Envelope Protein gp41, HIV-1, Humans, Immunoglobulin Fab Fragments, Interleukins, Kinetics, Models, Molecular, Molecular Sequence Data, Neutralization Tests, Peptides, Protein Engineering, Sequence Homology, Amino Acid, Surface Properties, Thermodynamics

Antibody Z13e1 is a relatively broadly neutralizing anti-human immunodeficiency virus type 1 antibody that recognizes the membrane-proximal external region (MPER) of the human immunodeficiency virus type 1 envelope glycoprotein gp41. Based on the crystal structure of an MPER epitope peptide in complex with Z13e1 Fab, we identified an unrelated protein, interleukin (IL)-22, with a surface-exposed region that is structurally homologous in its backbone to the gp41 Z13e1 epitope. By grafting the gp41 Z13e1 epitope sequence onto the structurally homologous region in IL-22, we engineered a novel protein (Z13-IL22-2) that contains the MPER epitope sequence for use as a potential immunogen and as a reagent for the detection of Z13e1-like antibodies. The Z13-IL22-2 protein binds Fab Z13e1 with a K(d) of 73 nM. The crystal structure of Z13-IL22-2 in complex with Fab Z13e1 shows that the epitope region is faithfully replicated in the Fab-bound scaffold protein; however, isothermal calorimetry studies indicate that Fab binding to Z13-IL22-2 is not a lock-and-key event, leaving open the question of whether conformational changes upon binding occur in the Fab, in Z13-IL-22, or in both.

Alternate JournalJ. Mol. Biol.
PubMed ID22033480