Design of functionalised circular tandem repeat proteins with longer repeat topologies and enhanced subunit contact surfaces.
Commun Biol 2021;
4:1240. [PMID:
34716407 PMCID:
PMC8556268 DOI:
10.1038/s42003-021-02766-y]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 10/07/2021] [Indexed: 01/16/2023] Open
Abstract
Circular tandem repeat proteins (‘cTRPs’) are de novo designed protein scaffolds (in this and prior studies, based on antiparallel two-helix bundles) that contain repeated protein sequences and structural motifs and form closed circular structures. They can display significant stability and solubility, a wide range of sizes, and are useful as protein display particles for biotechnology applications. However, cTRPs also demonstrate inefficient self-assembly from smaller subunits. In this study, we describe a new generation of cTRPs, with longer repeats and increased interaction surfaces, which enhanced the self-assembly of two significantly different sizes of homotrimeric constructs. Finally, we demonstrated functionalization of these constructs with (1) a hexameric array of peptide-binding SH2 domains, and (2) a trimeric array of anti-SARS CoV-2 VHH domains. The latter proved capable of sub-nanomolar binding affinities towards the viral receptor binding domain and potent viral neutralization function.
Jazmine Hallinan et al. report the development of a new generation of circular tandem repeat proteins with enhanced self-assembly. Functionalisation of these constructs with SARS CoV-2 VHH domains resulted in sub-nanomolar binding affinity to the viral receptor binding domain.
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