A Simple Tagging System for Protein Encapsulation

摘要

The encapsulation of cargo molecules by proteinaceous containers represents a potentially powerful strategy for the manufacture of novel materials,catalysts,or drug delivery systems.Indeed,many natural proteins self-assemble to form capsids that function as containers in a variety of biologically important processes.Examples include catalysis,iron storage by ferritin,the sequestration of non-native proteins by chaperones,and RNA/DNA transport by viral capsids.Many protein capsids are constructed by the self-assembly of multiple identical subunits.These complexes recognize their guests through noncovalent interactions and exploit the cooperativity afforded by symmetry to gain affinity and specificity.Protein engineering has been used to achieve the encapsulation of novel guests,often by hijacking naturally evolved recognition elements to serve in a new context.In a typical manifestation,the encapsulation of non-natural guests by virus particles has been driven via the fusion of a capsid-targeting peptide (derived from the physiological guest) to small molecules or other proteins.By engineering both the capsid and the cargo,binding interactions can be convergently designed and thus alleviate the need to mimic natural systems.