Verticilide, a new ryanodine-binding inhibitor, produced by Verticillium sp FKI-1033

A new ryanodine-binding inhibitor, verticilide, was isolated from the cultured broth of a fungus, Verticillium sp. FKI-1033. It is a 24-membered ring cyclic depsipeptide, its structure being elucidated as cyclo[(2R)-2-hydroxyheptanoyl-N-methyl-L-alanyl](4). Verticilide inhibited ryanodine binding to ryanodine receptors in the cockroach at an IC(50) value of 4.2 mu M, whereas inhibition against mouse ryanodine receptors was weak (IC(50)=53.9 mu M). The Journal of Antibiotics (2010) 63, 77-82; doi:10.1038/ja.2009.126; published online 8 January 2010