POHANG — An international research team co-led by Sangmin Lee of Pohang University of Science and Technology and David Baker of the University of Washington developed a design principle allowing a single artificial protein component to self-assemble into virus-like structures. This study, which was published in the journal Nature on May 21, enables the formation of pentagonal and hexagonal arrangements by the artificial protein component.

The research team utilized RFdiffusion, an AI-based protein structure generation tool, to create novel connecting structures. They then produced the designed artificial proteins using E. coli. Protein nanocages, which are hollow, nanometer-scale structures, form through the spontaneous binding of multiple proteins.

Viruses in nature assemble their shells using a single type of protein repeated hundreds to thousands of times, a process known as quasisymmetry. The designed proteins in this study spontaneously assembled into spherical shells. These shells varied in size, ranging from 70 nm to 220 nm.

The team observed the protein morphology through cryo-electron microscopy. The smallest assembled structure adopted a form resembling a soccer ball. Lee, a professor in the Department of Chemical Engineering at the university, said, "Viruses are the finest example in nature showing that perfect symmetry is not the only path to sophisticated molecular architecture."

The research was supported by programs from the Ministry of Science and ICT. David Baker is a professor at the University of Washington and received the 2024 Nobel Prize in Chemistry. The research team intends to conduct follow-up studies to achieve more uniform size control, planning to use internal scaffold proteins or nucleic acids as templates.