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Characterization of a novel Cu-containing dissimilatory nitrite reductase from the haloarchaeon Halorussus sp. YCN54.
Extremophiles ( IF 2.6 ) Pub Date : 2020-03-19 , DOI: 10.1007/s00792-020-01164-2
Jing Hou 1 , Xiao-Yan Yang 1 , Qin Xu 1 , Heng-Lin Cui 1
Affiliation  

Dissimilatory nitrite reductase, a key enzyme in the denitrification pathway, catalyzes the reduction of nitrite to NO. Bioinformatic analysis showed that the genome of a novel nitrite-degrading haloarchaeon Halorussus sp. YCN54 possessed a gene encoding the Cu-containing dissimilatory nitrite reductase (NirKHrs). NirKHrs was heterologously expressed and purified. Protein sequencing indicated that two isoforms of NirKHrs monomer were produced intracellularly. UV–vis spectrum of the purified NirKHrs showed that it belonged to the blue NirK group. NirKHrs showed optimum activity at 4.5 M NaCl, 55 ℃ and pH 7.0, representing a halophilic, slightly thermophilic and neutral enzyme. It exhibited high stability at 30–50 ℃. NirKHrs activity was strongly inhibited by the copper chelating agent due to removal of copper. NirKHrs activity was activated by Mn2+ and Sr2+. It displayed good tolerance to some high polarity organic solvents and nonionic surfactants, such as glycerol, DMSO, DMF and tween-20. Na2S2O4 was an effective electron donor to NirKHrs. The Km and Vmax values of purified NirKHrs for nitrite were 3.2 mM and 477.2 U/mg, respectively, indicating its high activity. These results indicated that NirKHrs may have potential applications for nitrite degradation in high-salt industries, such as salted food and saline wastewater treatment.

中文翻译:

表征的一种新型的含铜异亚硝酸盐还原酶,从嗜盐古龙Halorussus sp。YCN54。

亚硝酸盐还原酶是反硝化途径中的关键酶,催化亚硝酸盐还原为NO。生物信息学分析表明,一种新型的降解亚硝酸盐的卤代细菌Halorussus sp。的基因组。YCN54具有编码含Cu的异化亚硝酸盐还原酶(NirK Hrs)的基因。NirK Hrs是异源表达和纯化的。蛋白质测序表明,NirK Hrs单体的两种同工型在细胞内产生。纯化的NirK Hrs的紫外可见光谱表明,它属于蓝色NirK组。NirK小时在4.5 M NaCl,55℃和pH 7.0下显示最佳活性,代表一种嗜盐,略嗜热和中性的酶。在30–50℃时显示出高稳定性。由于去除了铜,NirK Hrs活性被铜螯合剂强烈抑制。NirK Hrs活性被Mn 2+和Sr 2+激活。它对某些高极性有机溶剂和非离子表面活性剂(如甘油,DMSO,DMF和tween-20)具有良好的耐受性。Na 2 S 2 O 4是NirK Hrs的有效电子供体。纯化的NirK HrsK mV max亚硝酸盐的活度分别为3.2 mM和477.2 U / mg,表明其高活性。这些结果表明,NirK Hrs可能在高盐行业(如盐渍食品和盐水废水处理)中对亚硝酸盐降解具有潜在的应用。
更新日期:2020-03-19
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