Mugineic acid
Mugineic acid is the organic compound consisting of a azetidine group and three carboxylates. A colorless solid, it is a siderophore. More specifically, it is a phytosiderophore, i.e. a plant-produced siderophore. It functions as an iron accumulating agent for barley and other plants. Related phytosiderophores include nicotianamine and avenic acid. It is biosynthesized from S-methylmethionine. The compound binds metal ions as a hexadentate ligand. References

Alpha-Amino acids
Gamma-Amino acids
Siderophores
Secondary amino acids
Tricarboxylic acids
Azetidines
Hexadentate ligands