9OT8

Crystal structure of Galectin-3 bound to FN3con-9 and FN3con-41, a cooperative binder that recognises the Galectin-3-FN3con-9 interface

Summary for 9OT8

• Entry DOI: 10.2210/pdb9ot8/pdb
• Descriptor: FN3con-9 - FN3con-41 fusion,Galectin-3 (2 entities in total)
• Functional Keywords: carbohydrate binding biosensor fibronectin type 3, carbohydrate
• Biological source: synthetic construct; More
• Total number of polymer chains: 1
• Total formula weight: 42015.92

Authors

Mutschler, R.,Caputo, A.T.,Guo, Z.,Fiorito, M.M.,Newton, S.,Zhang, X.,Karunathilaka, N.,Duval, C.,Brazel, H.,Abwanka, D.,Punyadeera, C.,Alexandrov, K.,Cui, Z. (deposition date: 2025-05-26, release date: 2026-05-20)

Primary citation

Mutschler, R.,Caputo, A.T.,Guo, Z.,Fiorito, M.M.,Hayat, I.F.,Newton, S.,Zhang, X.,Karunathilaka, N.,Duval, C.,Brazel, H.,Chan, W.,Kostner, K.,Korczyk, D.,Abankwa, D.K.,Atherton, J.J.,Coats, A.J.S.,Punyadeera, C.,Alexandrov, K.,Cui, Z.
Cooperative Binding Domains Enhance Sensitivity and Overcome the Hook Effect in Two-Component Protein Biosensors.
ACS Sens, 11:2870-2879, 2026

PubMed Abstract: Protein biosensors are important tools in research, bioengineering, and diagnostics. Unlike fully integrated single-component biosensors, two-component biosensors are modular and can be rapidly adapted to new targets by replacing binding elements. However, their utility is limited by a "hook effect," where high analyte concentrations lead to dissociation of the signalling complex and signal loss. We address this challenge by utilizing sequential mRNA display selection campaigns to develop high-affinity, cooperative FN3con (monobody) binding domains to Galectin-3, a protein biomarker of heart failure. Two-component biosensors equipped with such cooperative binders were devoid of the hook effect and demonstrated 5-fold higher sensitivity to Galectin-3 compared to systems based on non-cooperative binding domains. High-resolution crystal structures of cooperative and non-cooperative binding domains revealed how interactions between the two domains establish a cooperative Galectin-3 binding interface. The results and experimental approaches presented in this work enable the construction of high-performance biosensors for diverse applications.

PubMed: 41801969
DOI: 10.1021/acssensors.6c00488

Experimental method

X-RAY DIFFRACTION (1.96 Å)