Enzymatic Installation of Functional Molecules on Amyloid-Based Polymers.

We produced a functional polymer whose framework comprised transthyretin (TTR) amyloid fibrils. In order to immobilize functional molecules onto the amyloid fibrils, transpeptidase sortase A (srtA), which catalyzes the covalent binding of LPXTG with polyglycine, was employed. After the preparation of the amyloid fibril of LPETGG-tagged TTR, immobilization of Gly5-fused GFP on the amyloid fibrils by srtA-mediated transpeptidation was carried out. SrtA recognized the amyloid fibrils consisting of an LPETGG-tagged TTR variant (L55P) as a good substrate, resulting in successful preparation of a GFP-immobilized amyloid. Intriguingly, the replacement of GFP with Gly5-fused luciferase was confirmed when the GFP-immobilized amyloids were mixed with Gly5-luciferase in the presence of srtA. Thus, it was found that functional molecules covalently immobilized on amyloid could be detached and substituted with other tagged molecules by using srtA.