S100A7 (also Psoriasin) is an 11 - 13 kDa member of the S101 family, EF-hand superfamily of Ca-binding proteins. It is produced by keratinocytes and exists as both an intracellular and extracellular polypeptide. Intercellularly, it binds to E/FABP and may participate in fatty acid metabolism. Extracellularly, it is both monomeric and heterooligomeric and exhibits antibacterial properties. Human S100A7 is 101 amino acids (aa) in length. It contains two EF-hand motifs (aa 13 - 48 and 50 - 85), three zinc-binding His residues, one high-affinity Ca²⁺-binding site (aa 63 - 74) and an overlapping antibacterial sequence (aa 35 - 80). There appear to be no meaningful rodent structural orthologs of S100A7. Human S100A7 is 93% aa identical to human S100A15/7A, and the S100A7 gene has a duplication (S100A7B) that is 54% aa identical to S100A7.