The possibility to create a protein capsid, which can be reversibly opened and closed upon irradiation with light and packed with cargo of interest, would enhance our understanding of protein aggregation processes, and enable future synthesis of artificial enzymatic complexes or organelle assembly on-demand. Here, we want to decorate 11-meric rings of a TRAP protein with molecular photoswitches. This would create - at the outer rim of the rings – a binding interface with light-modulated polarity. In the hydrophobic state, multiple p-p-interactions between adjacent units should promote capsid assembly. In the polar state, with strongly reduced binding interactions, dissipation to subunits should prevail. Within this project, the optimal photoswitch structure and its connectivity to the protein will be investigated to achieve the desired effect - reversible light-triggered opening of a capsid. Subsequently, reversible light-modulated loading and unloading of the cage with biopolymers will be explored in vitro, using proteins and oligonucleotides as biorelevant cargo.