SpyTag–SpyCatcher (SpyTag/SpyCatcher)

SpyTag–SpyCatcher is a protein-protein ligation technology derived from the CnaB2 domain of the FbaB protein found in Streptococcus pyogenes (Zakeri et al., 2012). This system consists of a short peptide (SpyTag) and a larger protein partner (SpyCatcher) that spontaneously form an irreversible intermolecular isopeptide bond between a lysine residue on SpyCatcher and an aspartate residue on SpyTag (Li et al., 2014). This reaction is highly specific, rapid, and robust across various temperatures, pH levels, and buffer conditions (Keeble et al., 2019). While not a traditional therapeutic target like a receptor or enzyme, it serves as a powerful platform for the development of next-generation vaccines, protein-based therapeutics, and diagnostic tools. In vaccine development, it is frequently used to decorate virus-like particles (VLPs) with antigens to enhance immune responses against pathogens such as SARS-CoV-2 and Plasmodium falciparum (Bruun et al., 2018). Its primary role in disease management is as a modular assembly tool for complex biologics rather than a site for drug inhibition.

Other names

SpyTag/SpyCatcher systemSpyTag-SpyCatcherFbaB-derived peptide-protein pairCnaB2-derived ligation system

Spontaneous formation of a covalent intermolecular isopeptide bond between the side chains of Lys31 in SpyCatcher and Asp117 in SpyTag (Zakeri et al., 2012; Li et al., 2014).