Lasso-grafting of macrocyclic peptide pharmacophores yields multi-functional proteins

Protein engineering has great potential for devising multifunctional recombinant proteins to serve as next-generation protein therapeutics, but it often requires drastic modifications of the parental protein scaffolds e.g., additional domains at the N/C-terminus or replacement of a domain by another. A discovery platform system, called RaPID (Random non-standard Peptides Integrated Discovery) system, has enabled rapid discovery of small de novo macrocyclic peptides that bind a target protein with high binding specificity and affinity. Capitalizing on the optimized binding properties of the RaPID-derived peptides, here we show that RaPID-derived pharmacophore sequences can be readily implanted into surface-exposed loops on recombinant proteins and maintain both the parental peptide binding function(s) and the host protein function. We refer to this protein engineering method as lasso-grafting and demonstrate that it can endow specific binding capacity toward various receptors into a diverse set of scaffolds that includes IgG, serum albumin, and even capsid proteins of adeno-associated virus, enabling us to rapidly formulate and produce bi-, tri-, and even tetra-specific binder molecules. RaPID (Random non-standard Peptides Integrated Discovery) enables discovery of small macrocyclic peptides binding desired targets. Here, the authors propose lasso-grafting: the RaPID-derived peptides are implanted onto diverse proteins and maintain both the binding properties of the cyclic peptide and the host protein function.

Automated summary

The RaPID system enables rapid discovery of small macrocyclic peptides binding desired targets. The lasso-grafting method proposed here involves implanting RaPID-derived peptides onto diverse proteins while maintaining both the cyclic peptide's binding properties and the host protein function.