Calgranulins: S-100 domain found in proteins belonging to the Calgranulin subgroup of the S100 family of EF-hand calcium-modulated proteins, including S100A8, S100A9, and S100A12 . Note that the S-100 hierarchy, to which this Calgranulin group belongs, contains only S-100 EF-hand domains, other EF-hands have been modeled separately. These proteins are expressed mainly in granulocytes, and are involved in inflammation, allergy, and neuritogenesis, as well as in host-parasite response. Calgranulins are modulated not only by calcium, but also by other metals such as zinc and copper. Structural data suggested that calgranulins may exist in multiple structural forms, homodimers, as well as hetero-oligomers. For example, the S100A8/S100A9 complex called calprotectin plays important roles in the regulation of inflammatory processes, wound repair, and regulating zinc-dependent enzymes as well as microbial growth.
Structure:1E8A_A, Human S100A12 bound with calcium, contacts at 3.5A.
Comment:the N-terminal EF hand is a S100 specific feature while the C-terminal canonical EF hand is similar to the EF hands in calmodulin, troponin C, and parvalbumin
Comment:the second binding site (C-terminal EF hand) has a greater affinity for Ca2+ than the first (N-terminal EF hand)
Jiyao W et al.(2023). "The conserved domain database in 2023.",