Heryakusuma Christian, Johnson Eric F, Purwantini Endang, Mukhopadhyay Biswarup
Genetics, Bioinformatics, and Computational Biology Ph.D. Program, Virginia Tech, Blacksburg, VA 24061, USA.
Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA.
Access Microbiol. 2023 Apr 20;5(4). doi: 10.1099/acmi.0.000482.v3. eCollection 2023.
(), a hyperthermophilic and evolutionarily deeply rooted methanogenic archaeon from a deep-sea hydrothermal vent, produces F-dependent sulphite reductase (Fsr) in response to exposure to sulphite. This enzyme allows to detoxify sulphite, a potent inhibitor of methyl coenzyme-M reductase (Mcr), by reducing it to sulphide with reduced coenzyme F (FH) as an electron donor; Mcr is essential for energy production for a methanogen. Fsr allows to utilize sulphite as a sulphur source. Nitrite is another potent inhibitor of Mcr and is toxic to methanogens. It is reduced by most sulphite reductases. In this study, we report that Fsr reduced nitrite to ammonia with FH with physiologically relevant values (nitrite, 8.9 µM; FH, 9.7 µM). The enzyme also reduced hydroxylamine with a value of 112.4 µM, indicating that it was an intermediate in the reduction of nitrite to ammonia. These results open the possibility that could use nitrite as a nitrogen source if it is provided at a low concentration of the type that occurs in its habitat.
（）是一种来自深海热液喷口的嗜热且在进化上具有深厚根源的产甲烷古菌，在暴露于亚硫酸盐时会产生F依赖性亚硫酸盐还原酶（Fsr）。这种酶通过以还原型辅酶F（FH）作为电子供体将亚硫酸盐还原为硫化物，使（）能够解除亚硫酸盐（甲基辅酶-M还原酶（Mcr）的强效抑制剂）的毒性；Mcr对于产甲烷菌的能量产生至关重要。Fsr使（）能够将亚硫酸盐用作硫源。亚硝酸盐是Mcr的另一种强效抑制剂，对产甲烷菌有毒。大多数亚硫酸盐还原酶可将其还原。在本研究中，我们报告Fsr以FH将亚硝酸盐还原为氨，其具有生理相关的（亚硝酸盐，8.9 μM；FH，9.7 μM）。该酶还以112.4 μM的（值）还原羟胺，表明它是亚硝酸盐还原为氨过程中的中间体。这些结果开启了（）如果以其栖息地中出现的低浓度类型提供亚硝酸盐时可以将其用作氮源的可能性。
