synaptotagmin-like mitochondrial-lipid-binding protein (SMP) domain superfamily
The SMP domain is a lipid transport domain found in phospholipid transfer proteins such as synaptotagmin family proteins, tricalbin (TCB) family proteins, maintenance of mitochondrial morphology protein 1 (MMM1), mitochondrial distribution and morphology protein 12 (MDM12), mitochondrial distribution and morphology protein 34 (MDM34), PDZ domain-containing protein 8 (PDZD8), testis-expressed protein 2 (TEX2), meiotically up-regulated gene 190 protein (Mug190), C2 domain-containing protein 2 (C2CD2) and C2 domain-containing protein 2-like (C2CD2L). The SMP domain belongs to a superfamily of lipid/hydrophobic ligand-binding domains called TULIP (tubular lipid-binding proteins). It adopts a TULIP fold with two alpha helices and a highly curved antiparallel beta sheet forming a cornucopia-like structure.
Jiyao W et al.(2023). "The conserved domain database in 2023.",