PMID: 26672965 , Related PDB ids: 3X3F, 3X3G

Authors:

Tamada T, Shinmi D, Ikeda M, Yonezawa Y, Kataoka S, Kuroki R, Mori E, Motoki K

Title:

TRAIL-R2 Superoligomerization Induced by Human Monoclonal Agonistic Antibody KMTR2.

Journal:

Sci Rep. 2015 Dec 17;5:17936. doi: 10.1038/srep17936.

Abstract:

The fully human monoclonal antibody KMTR2 acts as a strong direct agonist for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2 (TRAIL-R2), which is capable of inducing apoptotic cell death without cross-linking. To investigate the mechanism of direct agonistic activity induced by KMTR2, the crystal structure of the extracellular region of TRAIL-R2 and a Fab fragment derived from KMTR2 (KMTR2-Fab) was determined to 2.1 A resolution. Two KMTR2-Fabs assembled with the complementarity-determining region 2 of the light chain via two-fold crystallographic symmetry, suggesting that the KMTR2-Fab assembly tended to enhance TRAIL-R2 oligomerization. A single mutation at Asn53 to Arg located at the two-fold interface in the KMTR2 resulted in a loss of its apoptotic activity, although it retained its antigen-binding activity. These results indicate that the strong agonistic activity, such as apoptotic signaling and tumor regression, induced by KMTR2 is attributed to TRAIL-R2 superoligomerization induced by the interdimerization of KMTR2.