2.B.4 The Macrotetrolide Antibiotic (MA) Family

The macrotetrolide antibiotics include nonactin, monactin, dinactin and trinactin. They can complex and transport a variety of monovalent cations with affinities in the order Li+ > Na+ > Cs+ > K+ > Rb+ > NH4+. These monocyclic antibiotics exhibit a fairly high degree of cation selectivity. In contrast to nigericin and monensin, and like valinomycin, they can function as uniporters and therefore conduct currents.

The generalized transport reaction (uniport) catalyzed by MA family members is:

M+ (in) M+ (out)



Eisenman, G., G. Szabo, S.G.A. McLaughlin and S.M. Ciani (1973). Molecular basis for the action of macrocyclic carriers on passive ionic translocation across lipid bilayer membranes. Bioenergetics 4: 93-148.

Harold, F.M., K.H. Altendorf and H. Hirata (1974). Probing membrane transport mechanisms with ionophores. Annals N.Y. Acad. Sci. 235: 149-160.

Kilbourn, B.T., J.D. Dunitz, L.A. Pioda, and W. Simon. (1967). Structure of the K+ complex with nonactin, a macrotetrolide antibiotic possessing highly specific K+ transport properties. J. Mol. Biol. 30: 559-563.