Dendrimer‐Like Supramolecular Assembly of Proteins with a Tunable Size and Valency Through Stepwise Iterative Growth

The assembly of proteins in a programmable manner provides insight into the creation of novel functional nanomaterials for practical applications. Despite many advances, however, a rational protein assembly with an easy scalability in terms of size and valency remains a challenge. Here, a simple bottom‐up approach to the supramolecular protein assembly with a tunable size and valency in a programmable manner is presented. The dendrimer‐like protein assembly, simply called a “protein dendrimer,” is constructed through a stepwise and alternate addition of a building block protein. Starting from zeroth‐generation protein dendrimer (pG 0 ) of 27 kDa, the protein dendrimer is sequentially grown to pG 1 , pG 2 , pG 3 , to pG 4 with a molecular mass of 94, 216, 483, and 959 kDa, respectively. The valency of the protein dendrimers at the periphery increases by a factor of two after each generation, allowing a tunable valency and easy functionalization. The protein dendrimers functionalizes with a targeting moiety and a cytotoxic protein cargo shows a typical feature of multi‐valency in the avidity and a highly enhanced cellular cytotoxicity, exemplifying their utility as a protein delivery platform. The present approach can be effectively used in the creation of protein architectures with new functions for biotechnological and medical applications.