Rosenbaum Florian P, Poehlein Anja, Daniel Rolf, Müller Volker
Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt, Germany.
Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August University Göttingen, Göttingen, 37077, Germany.
Environ Microbiol. 2022 Apr;24(4):2000-2012. doi: 10.1111/1462-2920.15971. Epub 2022 Mar 12.
Moorella thermoacetica is one of the well-studied thermophilic acetogenic bacteria. It grows by oxidation of organic substrates, CO or H coupled to CO reduction to acetate. Here, we describe that M. thermoacetica can also use dimethyl sulfoxide as terminal electron acceptor. Growth of M. thermoacetica on glucose or H + CO was stimulated by dimethyl sulfoxide (DMSO). Membranes showed a DMSO reductase activity, that was induced by growing cells in presence of DMSO. The enzyme used reduced anthraquinone-2,6-disulfonate, benzyl- and methyl viologen as electron donor, but not NAD(P)H. Activity was highest at pH 5 and 60°C, the Km for DMSO was 2.4 mM. Potential DMSO reductase subunits were identified by peptide mass fingerprinting; they are encoded in a genomic region that contains three potential dmsA genes, three dmsB genes and one dmsC gene. Transcriptome analysis revealed that two different dmsAB gene clusters were induced in the presence of DMSO. The function of these two and their predicted biochemical features are discussed. In addition, the data are in line with the hypothesis that M. thermoacetica can use DMSO alongside CO as electron acceptor and DMSO reduction is catalysed by an energy-conserving, membrane-bound electron transport chain with DMSO as final electron acceptor.
嗜热栖热菌是一种经过充分研究的嗜热产乙酸细菌。它通过氧化有机底物、CO或H并将CO还原为乙酸来生长。在此，我们描述嗜热栖热菌还可以使用二甲基亚砜作为末端电子受体。二甲基亚砜（DMSO）刺激了嗜热栖热菌在葡萄糖或H + CO上的生长。细胞膜表现出DMSO还原酶活性，该活性是由在DMSO存在下生长的细胞诱导产生的。该酶使用还原型蒽醌-2,6-二磺酸盐、苄基紫精和甲基紫精作为电子供体，但不使用NAD(P)H。活性在pH 5和60°C时最高，DMSO的Km为2.4 mM。通过肽质量指纹图谱鉴定了潜在的DMSO还原酶亚基；它们编码在一个基因组区域中，该区域包含三个潜在的dmsA基因、三个dmsB基因和一个dmsC基因。转录组分析表明，在DMSO存在下，两个不同的dmsAB基因簇被诱导。讨论了这两个基因簇的功能及其预测的生化特征。此外，这些数据符合以下假设：嗜热栖热菌可以将DMSO与CO一起用作电子受体，并且DMSO的还原是由以DMSO为最终电子受体的节能膜结合电子传递链催化的。
