21TV

Cryo-EM structure of the TNF-alpha-Ozoralizumab (OZR)-HSA complex

Summary for 21TV

• Entry DOI: 10.2210/pdb21tv/pdb
• EMDB information: 67993
• Descriptor: Ozoralizumab (OZR), Tumor necrosis factor, Serum albumin (3 entities in total)
• Functional Keywords: nanobody, vhh, tnf-alpha, hsa, ozoralizumab, ozr, cytokine
• Biological source: Homo sapiens; More
• Total number of polymer chains: 5
• Total formula weight: 157326.01

Authors

Tanaka, Y.,Sato, K.,Mima, M.,Mishima-Tsumagari, C. (deposition date: 2025-12-26, release date: 2026-04-29)

Primary citation

Mima, M.,Sato, K.,Yokoyama, T.,Mishima-Tsumagari, C.,Ohnuki, T.,Tanaka, Y.,Iwamoto, K.
Cryo-EM elucidates the interaction mechanism of ozoralizumab, a humanized anti-TNF alpha NANOBODY® compound.
Biochem.Biophys.Res.Commun., 816:153572-153572, 2026

PubMed Abstract: Ozoralizumab (OZR) is a next-generation TNF inhibitor composed of two identical humanized anti-TNFα NANOBODY® molecules (TNF30s) recombinantly linked via one humanized anti-human serum albumin (HSA) NANOBODY® molecule (ALB8) and two peptide linkers. OZR is designed as a unique format to exert potent inhibitory effects against TNFα with long plasma half-life. However, the three-dimensional structure of OZR-TNFα-HSA complex has not yet been elucidated, and a complete understanding of its interaction mechanism with TNFα is yet to be gained. In this study, we successfully observed the formation of the OZR-TNFα-HSA ternary complex by single-particle cryo-electron microscopy. The single-particle analysis revealed that the two TNF30 molecules of OZR simultaneously bind bivalently to TNFα in a 1:1-bivalent binding mode, while the ALB8 molecule binds to HSA, forming a ternary complex. Thus, OZR exhibits a binding mode significantly different from that of other IgG-type TNFα inhibitors. Furthermore, surface plasmon resonance (SPR) analysis demonstrated that the 1:1-bivalent binding mode confers an exceptionally slow dissociation rate, thereby contributing to the potent TNFα-neutralizing activity of OZR. These findings not only lend support to the favorable clinical efficacy of OZR from a structural standpoint but also lay the foundation for the rational design and development of next-generation TNFα inhibitors with enhanced and sustained efficacy.

PubMed: 41935434
DOI: 10.1016/j.bbrc.2026.153572

Experimental method

ELECTRON MICROSCOPY (6.19 Å)