In our new work we showed that in certain conditions, mixing modified TRAP ring-shaped protein with small (1-3 nm) gold nanoparticles resulted in an unusual protein cage made from twelve protein rings arranged in a way similar to a dodecahedron. Interestingly, the gaps at the “corners” of the shape were filled with individual gold nanoparticles around 1.5 nm in diameter. So the protein cage acts as a scaffold for the regular arrangement of the nanoparticles in a tiny 3D lattice. In the future it would be interesting to know if arranging metal nanoparticles in this way could lead to useful properties. The image above shows the cryo-EM based density map of the new cage. The twelve rings are shown in purple while four of the embedded golds are showm in yellow. Well done to the whole team, first author Karolina Majsterkiewicz and our collaborators Bernard Piette and Wouter Roos. The paper was published in Nano Letters. Access it here.