Engineering defensin α-helix to produce high-affinity SARS-CoV-2 spike protein binding ligands.

The binding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein to the angiotensin-converting enzyme 2 (ACE2) receptor expressed on the host cells is a critical initial step for viral infection. This interaction is blocked through competitive inhibition by soluble ACE2 protein. Therefore, developing high-affinity and cost-effective ACE2 mimetic ligands that disrupt this protein-protein interaction is a promising strategy for viral diagnostics and therapy. We employed human and plant defensins, a class of small (2-5 kDa) and highly stable proteins containing solvent-exposed alpha-helix, conformationally constrained by two disulfide bonds. Therefore, we engineered the amino acid residues on the constrained alpha-helix of defensins to mimic the critical residues on the ACE2 helix 1 that interact with the SARS-CoV-2 spike protein. The engineered proteins (h-deface2, p-deface2, and p-deface2-MUT) were soluble and purified to homogeneity with a high yield from a bacterial expression system. The proteins demonstrated exceptional thermostability (Tm 70.7°C), high-affinity binding to the spike protein with apparent K

Informations de copyright

© 2022 The Protein Society.