5k64

Publication Abstract from PubMed

Fcabs (Fc domain with antigen-binding sites) are promising novel therapeutics. By engineering of the C-terminal loops of the CH3 domains, two antigen binding sites can be inserted in close proximity. In order to elucidate the binding mode(s) between homodimeric Fcabs and small homodimeric antigens, the interaction between the Fcabs 448 and CT6 (having the AB, CD and EF loops and the C-termini engineered) with homodimeric VEGF was investigated. The crystal structures of these Fcabs, which form polymers with the antigen VEGF in solution, were determined. However, construction of heterodimeric Fcabs (JanusFcabs: one chain Fc-wt, one chain VEGF-binding) results in formation of distinct JanusFcab-VEGF complexes (2:1), which allowed elucidation of the crystal structure of the JanusCT6-VEGF complex at 2.15 A resolution. VEGF binding to Janus448 and JanusCT6 is shown to be entropically unfavorable, but enthalpically favorable. Structure-function relationships are discussed with respect to Fcab design and engineering strategies.

Two-Faced Fcab Prevents Polymerization with VEGF and Reveals Thermodynamics and the 2.15 A Crystal Structure of the Complex.,Lobner E, Humm AS, Mlynek G, Kubinger K, Kitzmuller M, Traxlmayr MW, Djinovic-Carugo K, Obinger C MAbs. 2017 Aug 17:0. doi: 10.1080/19420862.2017.1364825. PMID:28816592^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.