Metal-free S100A3, a cysteine-rich Ca²⁺- and Zn²⁺-binding protein, has been crystallized by vapour diffusion under the strict exclusion of oxygen and in the absence of divalent metal ions. The structure was solved by MIRAS phasing using potassium iodide and xenon derivatives.

Human recombinant EF-hand Ca²⁺-binding protein S100B has been purified and crystallized. A complete data set was recorded to 1.9 Å.