Lipscomb Gina L, Schut Gerrit J, Scott Robert A, Adams Michael W W
Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.
Mol Microbiol. 2017 Jun;104(5):869-881. doi: 10.1111/mmi.13668. Epub 2017 Apr 18.
The sulfur response regulator, SurR, is among a handful of known redox-active transcriptional regulators. First characterized from the hyperthermophile Pyrococcus furiosus, it is unique to the archaeal order Thermococcales. P. furiosus has two modes of electron disposal. Hydrogen gas is produced when the organism is grown in the absence of elemental sulfur (S ) and H S is produced when grown in its presence. Switching between these metabolic modes requires a rapid transcriptional response and this is orchestrated by SurR. We show here that deletion of SurR causes severely impaired growth in the absence of S since genes essential for H metabolism are no longer activated. Conversely, a strain containing a constitutively active SurR variant displays a growth phenotype in the presence of S due to constitutive repression of S -responsive genes. During a metabolic shift initiated by addition of S to the growth medium, both strains demonstrate a de-regulation of genes involved in the SurR regulon, including hydrogenase and related S -responsive genes. These results demonstrate that SurR is a master regulator of electron flow within P. furiosus, likely affecting the pools of ferredoxin, NADPH and NADH, as well as influencing metabolic pathways and thiol/disulfide redox balance.
硫响应调节因子SurR是少数已知的具有氧化还原活性的转录调节因子之一。它最初是在嗜热古菌激烈火球菌中被鉴定出来的，是嗜热栖热菌目古菌所特有的。激烈火球菌有两种电子处理模式。当该生物体在没有元素硫（S）的情况下生长时会产生氢气，而在有元素硫存在的情况下生长时会产生硫化氢（H₂S）。在这些代谢模式之间切换需要快速的转录反应，而这是由SurR精心调控的。我们在此表明，缺失SurR会导致在没有S的情况下生长严重受损，因为氢代谢所必需的基因不再被激活。相反，含有组成型活性SurR变体的菌株由于S响应基因的组成型抑制，在有S存在时表现出一种生长表型。在向生长培养基中添加S引发的代谢转变过程中，两种菌株都表现出参与SurR调控子的基因失调，包括氢化酶和相关的S响应基因。这些结果表明，SurR是激烈火球菌内电子流的主要调节因子，可能影响铁氧化还原蛋白、NADPH和NADH的水平，以及影响代谢途径和硫醇/二硫键氧化还原平衡。
