Stigmatellin. A dual type inhibitor of photosynthetic electron transport

Abstract

Stigmatellin, an antibiotic produced by the myxobacterium Stigmatella aurantiaca, is a powerful inhibitor of photosynthetic electron transport. In the photosynthetic electron-transport chain, it has two different inhibition sites. One is located at the reducing side of Photosystem II ( I 50 value, 52.5 nM) and identical to the inhibition site of inhibitors of the 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea type. The second one is located at the cytochrome b 6 f- complex ( I 50 value, 59.0 nM) and corresponds to the inhibition site of 2.5-dibromo-3-methyl-6-isopropyl-1,4-benzoquinone. Stigmatellin is the most potent inhibitor of spinach cytochrome b 6 f complex known so far.