Development and characterization of small bispecific three-helical ErbB3/albumin-binding domains aimed at therapeutic applications
(English)Manuscript (preprint) (Other academic)
Affinity proteins based on small scaffolds are currently emerging as alternatives to antibodies for therapy. Similarly to antibodies, they can be engineered to have high affinity for specific proteins. A potential problem with small proteins and peptides is their short in vivo circulation time, which might limit the therapeutic efficacy. To circumvent this issue, we have engineered bispecificity into an albumin-binding domain (ABD) derived from streptococcal protein G. The inherent albumin binding was preserved while the opposite side of the molecule was randomized to create a flexible surface for selection of high-affinity binders. Here we present novel ABD-variants selected by phage display with the ability to bind to the epidermal growth factor receptor 3 (ErbB3). Isolated candidates were thoroughly characterized regarding affinity and stability. Importantly, they were shown to still have affinity to albumin, hence demonstrating that the intended strategy to engineer bispecific single-domain proteins was successful. Moreover, competition assays revealed that the new binders could block the natural ligand Neuregulin from binding to ErbB3, indicating a potential anti-proliferative effect. These new binders thus represent promising candidates for further development into ErbB3-signaling inhibitors, where the albumin interaction could result in prolonged in vivo half-life.
Albumin-binding domain, ABD, phage display, ErbB3, human serum albumin, HSA, bispecific
IdentifiersURN: urn:nbn:se:kth:diva-105514OAI: oai:DiVA.org:kth-105514DiVA: diva2:571298
QS 20122012-11-222012-11-222012-11-22Bibliographically approved