[Free radicals in mercury-resistant bacteria indicate a novel metabolic pathway].

A mercury resistant-soil bacterium P.10.15, identified as a close relative of Pseudomonas veronii, was shown to accumulate a specific compound in the stationary phase of growth. This compound is converted to a long-lived free radical under oxidizing conditions, as registered by its EPR signal at room temperature. The compound was purified by ion-exchange and gel-filtration chromatography and identified by mass spectroscopy, 2D NMR, and EPR as a trisaccharide beta-D-GlcpNOH,CH3-(1-->6)-alpha-D-Glcp-(1-->1)-alpha-D-Glcp, or, in other words, as 6-O-(2-deoxy-2-[N-methyl]hydroxylamino-beta-D- glucopyranosyl)-alpha-alpha-trehalose, previously discovered in Micrococcus luteus (lysodeikticus) and named lysodektose. The compound is suggested to be a novel intermediate of a previously unknown basic metabolic pathway of trehalose transformation in bacteria, a potential target for antibacterial drug development.