Find in Library

Plant-produced isoprene (2-methyl-1,3-butadiene) represents a significant portion of global volatile organic compound production, equaled only by methane. A metabolic pathway for the degradation of isoprene was first described for the Gram-positive bacterium <i>Rhodococcus </i>sp<i>. </i>AD45, and an alternative model organism has yet to be characterised. Here, we report the characterisation of a novel Gram-negative isoprene-degrading bacterium, <i>Variovorax </i>sp<i>. </i>WS11. Isoprene metabolism in this bacterium involves a plasmid-encoded <i>iso</i> metabolic gene cluster which differs from that found in <i>Rhodococcus </i>sp<i>. </i>AD45 in terms of organisation and regulation. Expression of <i>iso</i> metabolic genes is significantly upregulated by both isoprene and epoxyisoprene. The enzyme responsible for the initial oxidation of isoprene, isoprene monooxygenase, oxidises a wide range of alkene substrates in a manner which is strongly influenced by the presence of alkyl side-chains and differs from other well-characterised soluble diiron monooxygenases according to its response to alkyne inhibitors. This study presents <i>Variovorax </i>sp<i>. </i>WS11 as both a comparative and contrasting model organism for the study of isoprene metabolism in bacteria, aiding our understanding of the conservation of this biochemical pathway across diverse ecological niches.