Ring-like nanoparticle arrays, not accessable via any of the conventional synthetic methods, are synthesized by a rapid and straightforward method. Calcium ions direct the assembly of tubulin into spiral-shaped protein structures, which provide a tool to control the deposition of Ag nanoparticles into spiral-shaped arrays along the backbone of the biostructure (see Figure). This synthetic capability creates the potential of wet-chemical synthesis of nanosized metallic ring structures.