Nigericin
Nigericin is an antibiotic derived from Streptomyces hygroscopicus. Its isolation was described in the 1950s, and in 1968 the structure could be elucidated by X-ray crystallography. The structure and properties of nigericin are similar to the antibiotic monensin. Commercially it is obtained as a byproduct, or contaminant, at the fermentation of Geldanamycin. It is also called Polyetherin A, Azalomycin M, Helixin C, Antibiotic K178, Antibiotic X-464.
Nigericin acts as an H+, K+, Pb2+ ionophore. Most commonly it is an antiporter of H+ and K+.
In the past nigericin was used as an antibiotic active against gram positive bacteria. It inhibits the Golgi functions in Eukaryotic cells. Its ability to induce K+ efflux also makes it a potent activator of the NLRP3 inflammasome