Isoprene Oxidation by the Gram-Negative Model bacterium Variovorax sp. WS11
Isoprene Oxidation by the Gram-Negative Model bacterium Variovorax sp. WS11
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DOI：
10.3390/microorganisms8030349
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发表时间：
2020-03-01
期刊：
影响因子：
4.5
通讯作者：
Murrell, J. Colin
中科院分区：
文献类型：
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作者：
Dawson, Robin A.;Larke-Mejia, Nasmille L.;Murrell, J. Colin
植物生产的异戊二烯（2-甲基-1，3-丁二烯）占全球挥发性有机化合物产量的很大一部分，仅次于甲烷。异戊二烯降解的代谢途径首先被描述为革兰氏阳性细菌红球菌属AD 45，另一种模式生物尚未被表征。在这里，我们报告了一种新的革兰氏阴性异戊二烯降解菌，Variovorax sp. WS 11的特性。在这种细菌中的异戊二烯代谢涉及质粒编码的异代谢基因簇，其在组织和调节方面不同于在红球菌属AD 45中发现的异代谢基因簇。异戊二烯和环氧异戊二烯均显著上调异源代谢基因的表达。负责异戊二烯的初始氧化的酶，异戊二烯单加氧酶，以受到烷基侧链的存在的强烈影响的方式氧化广泛的烯烃底物，并且根据其对炔抑制剂的响应而不同于其它充分表征的可溶性二铁单加氧酶。本研究提出Variovorax sp. WS 11作为一个比较和对比的模式生物异戊二烯代谢的研究在细菌中，帮助我们了解这种生物化学途径的保护在不同的生态位。
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 Rhodococcus sp. AD45, and an alternative model organism has yet to be characterised. Here, we report the characterisation of a novel Gram-negative isoprene-degrading bacterium, Variovorax sp. WS11. Isoprene metabolism in this bacterium involves a plasmid-encoded iso metabolic gene cluster which differs from that found in Rhodococcus sp. AD45 in terms of organisation and regulation. Expression of iso 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 Variovorax sp. 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.