BtrN catalyzes the two-electron oxidation of the C3 secondary alcohol of 2-deoxy-scyllo-inosamine to the corresponding ketone, and is a member of a subclass of radical S-adenosylmethionine (SAM) enzymes called radical SAM (RS) dehydrogenases. As do all RS enzymes, BtrN contains a [4Fe–4S] cluster that delivers an electron to SAM, inducing its cleavage to the common intermediate in RS reactions, the 5’-deoxyadenosyl 5’-radical. In this work, it is shown that BtrN contains an additional [4Fe–4S] cluster, suggested to bind in contact with the substrate to facilitate loss of the second electron in the two-electron oxidation.

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Lantana (Lantana camara Linn) is a noxious weed that grows in many tropical and subtropical parts of the world. Ingestion of lantana foliage by grazing animals causes cholestasis and hepatotoxicity. Both ruminants and nonruminant animals such as guinea pigs, rabbits, and female rats are susceptible to the hepatotoxic action of lantana toxins. The hepatotoxins are pentacyclic triterpenoids called lantadenes. Molecular structure of lantadenes has been determined. Green unripe fruits of the plant are toxic to humans. Lantana spp. exert allelopathic action on the neighboring vegetation. The allelochemicals have been identified as phenolics, with umbelliferone, methylcoumarin, and salicylic acid being the most phytotoxic. In addition to phenolics, a recent report indicates lantadene A and B as more potent allelochemicals. Management of lantana toxicosis in animals is achieved by drenching with activated charcoal and supportive therapy. Recent reports on the bilirubin clearance effect of Chinese herbal tea Yin Zhi Huang (decoction of the plant Yin Chin, Artemisia capillaries, and three other herbs) or its active ingredient 6,7-dimethylesculetin, in jaundice are very exciting and warrant investigations on its, possible, ameliorative effects in lantana intoxicated animals. Research is being conducted on new drug discovery based on natural products in different parts of the lantana plant.

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