Probing for a colon cancer toxin

Abstract

A DNA-damaging toxin called colibactin could mark the onset of colon cancer. Up to 67% of people with colon cancer harbor strains of Escherichia coli in their guts that produce colibactin, compared with only 20% of those without the disease. But scientists still don’t know colibactin’s complete structure because no one has isolated the compound. A team led by Kenji Watanabe of the University of Shizuoka has developed a fluorescent probe that allows fast, high-throughput screening of colibactin-producing bacteria and identification of high-producing strains (Org. Lett. 2019, DOI: 10.1021/acs.orglett.9b01345). Such strains could make isolating the compound and determining its complete structure easier, the researchers say. The researchers probed for ClbP, a peptidase that is part of late-stage colibactin synthesis. It removes a protective group from the colibactin precursor. To make their probe, researchers attached a fluorescent tag to the protective group and delivered it to bacterial cultures. Active Clb...