Conformational Heterogeneity in Antibody-Protein Antigen Recognition

• DOI: 10.1074/jbc.m113.492215
• Publication Date: 2014-01-17T03:17:59Z
• Authors: Philip W. Addis; Catherine J. Hall; Shaun Bruton; Vaclav Veverka; Ian C. Wilkinson; Frederick W. Muskett; Philip S. Renshaw; Christine E. Prosser; Bruce Carrington; Alastair D.G. Lawson; Robert Griffin; Richard J. Taylor; Lorna C. Waters; Alistair J. Henry; Mark D. Carr
• Keywords: 0303 health sciences; Interleukin-6; Interleukin-1beta; Molecular Sequence Data; Antibody Affinity; Antigen-Antibody Complex; Antibodies, Monoclonal, Humanized; Protein Structure, Secondary; Immunoglobulin Fab Fragments; 03 medical and health sciences; Humans; Amino Acid Sequence; Antigens; Nuclear Magnetic Resonance, Biomolecular

Specific, high affinity protein-protein interactions lie at the heart of many essential biological processes, including recognition an apparently limitless range foreign proteins by natural antibodies, which has been exploited to develop therapeutic antibodies. To mediate protein complexes need form on appropriate, relatively rapid timescales, presents a challenge for productive engagement with large and complex contact surfaces (∼600-1800 Å(2)). We have obtained comprehensive backbone NMR assignments two distinct, antibody fragments (single chain variable antigen-binding (Fab) fragments), recognize structurally diverse cytokines interleukin-1β (IL-1β, β-sheet) interleukin-6 (IL-6, α-helical). studies revealed that hearts antigen binding sites in both free anti-IL-1β Fab anti-IL-6 single exist multiple conformations, interconvert timescale comparable rates antibody-antigen formation. In addition, we identified conserved binding-induced change orientation domains. The observed conformational heterogeneity slow dynamics appears be feature interfaces characterized NMR, suggesting role propose this behavior may reflect soft capture, docking mechanism, facilitating formation consistent processes.