30GR | pdb_000030gr

DOTAM-TCB: Universal Small Molecule-Guided Hapten- and T Cell Bispecfic Antibodies for Cancer Immunotherapy

PDB DOI: https://doi.org/10.2210/pdb30GR/pdb

Classification: IMMUNE SYSTEM
Organism(s): Homo sapiens
Expression System: Homo sapiens
Mutation(s): No

Deposited: 2026-04-24 Released: 2026-10-14
Deposition Author(s): Ehler, A., Klein, C., Surowka, M., Venetz, D., Benz, J.
Funding Organization(s): Not funded

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 1.45 Å
R-Value Free:
0.208 (Depositor), 0.208 (DCC)
R-Value Work:
0.180 (Depositor), 0.180 (DCC)
R-Value Observed:
0.181 (Depositor)

Starting Model: experimental
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wwPDB Validation 3D Report Full Report

This is version 1.0 of the entry. See complete history.

Literature

DOTAM-TCB: Universal Small Molecule-guided Hapten- and T Cell-bispecific Antibodies for Cancer Immunotherapy.

Surowka, M., Kober, T., Matscheko, D., Ehler, A., Macedo, W., Assisi, D., Challier, J., Sobieniecki, A., Gianotti, R., Bransi, A., Sam, J., Bonfiglio, J.J., Wichert, M., Ricci, A., Benz, J., Umana, P., Venetz, D., Klein, C.

(2026) Antib Ther 9: 535-549

PubMed: 42824820 Search on PubMed Search on PubMed Central
DOI: https://doi.org/10.1093/abt/tbag038
Primary Citation Related Structures:
30GR

PubMed Abstract:
Tumor heterogeneity has been identified as a major roadblock for cancer immunotherapy. To overcome this, universal effector cell engagers with interchangeable tumor-targeting adaptors have been developed. Current concepts in this field consist of antibody-based adaptors. Small-molecule (SM) ligands, on the other hand, infiltrate tissues rapidly, have short half-lives, and are potentially orally available. Therefore, we hypothesized that utilizing SM adaptors, combined with effector antibodies, could represent an attractive off-the-shelf therapy. Here, we introduce the development of target-agnostic, small-molecule-guided hapten- and T cell-bispecific (TCB) antibodies with high affinity between the adaptor-effector pair. Specifically, we designed SM adaptors based on known tumor-targeting ligands with specificity to the antigens folate receptor 1 (FOLR1), prostate-specific membrane antigen (PSMA) and carbonic anhydrase IX (CAIX), and conjugated them to Ca ²⁺-loaded 1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane (DOTAM) as a hapten. As an effector antibody, we designed DOTAM-specific T cell bispecific antibodies (DOTAM-TCB) with femtomolar (fM) affinity for the hapten. In vitro experiments showed in-solution assembly of stable adaptor-effector complexes. Additionally, T cell-mediated tumor killing was initiated by the universal DOTAM-TCB when combined with adaptors across various tumor cells. Ex vivo study of CAIX-directed Ca-DOTAM-acetazolamide (Ca-DOTAM-AAZ) with DOTAM-TCB showed potent activation of T cells against murine-engrafted human HT-29 tumor. The studies described here demonstrate proof-of-concept for using hapten-containing small molecules as adaptors for effective universal T cell engager-based cancer immunotherapy.

Organizational Affiliation

Roche Pharma Research and Early Development, Roche Innovation Center Zurich, 8952 Schlieren, Switzerland.

Macromolecule Content

Total Structure Weight: 48.33 kDa
Atom Count: 3,908
Modeled Residue Count: 442
Deposited Residue Count: 442
Unique protein chains: 2

Macromolecules

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| 3D Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
FAB Fragment Heavy Chain	A [auth H]	224	Homo sapiens	Mutation(s): 0
Entity Groups
Sequence Clusters	30% Identity 50% Identity 70% Identity 90% Identity 95% Identity 100% Identity
Sequence Annotations Expand
Reference Sequence

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| 3D Structure

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
FAB Fragment Light chain	B [auth L]	218	Homo sapiens	Mutation(s): 0
Entity Groups
Sequence Clusters	30% Identity 50% Identity 70% Identity 90% Identity 95% Identity 100% Identity
Sequence Annotations Expand
Reference Sequence

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram	3D Interactions
A1J6R( Subject of Investigation/LOI) Query on A1J6R Download:Ideal Coordinates CCD File SDF format, chain C [auth H] MOL2 format, chain C [auth H] mmCIF format, chain C [auth H]	C [auth H]	~{N}-(5-sulfamoyl-1,3,4-thiadiazol-2-yl)-8-[[4-[[(2~{S})-1,4,7,10-tetrakis(2-azanyl-2-oxidanylidene-ethyl)-1,4,7,10-tetrazacyclododec-2-yl]methyl]phenyl]carbamothioylamino]octanamide C₃₄ H₅₆ N₁₄ O₇ S₃ YKQZLPSQSBTLEK-SANMLTNESA-N		Interactions Focus chain C [auth H] Interactions & Density Focus chain C [auth H]
CA Query on CA Download:Ideal Coordinates CCD File SDF format, chain D [auth H] MOL2 format, chain D [auth H] mmCIF format, chain D [auth H]	D [auth H]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N		Interactions Focus chain D [auth H] Interactions & Density Focus chain D [auth H]