Structural polymorphism in protein cages and virus-like particles.

Protein cages and virus-like particles are often thought of as highly uniform structures that obey strict geometric rules for self-assembly. Yet, there is a growing number of examples where different architectures can emerge from the same native cage system through minor changes in experimental conditions or protein sequence. Access to diverse architectures can help tune the engineering of protein cages for biotechnology applications where shape and symmetry often affects function. In this review, we highlight the underappreciated diversity of polymorphic architectures that can be formed by protein cages and virus-like particles, categorising examples by their method of formation.