Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
Mol Microbiol. 2019 Jun;111(6):1592-1603. doi: 10.1111/mmi.14239. Epub 2019 Apr 6.
Nitrate is available to microbes in many environments due to sustained use of inorganic fertilizers on agricultural soils and many bacterial and archaeal lineages have the capacity to express respiratory (Nar) and assimilatory (Nas) nitrate reductases to utilize this abundant respiratory substrate and nutrient for growth. Here, we show that in the denitrifying bacterium Paracoccus denitrificans, NarJ serves as a chaperone for both the anaerobic respiratory nitrate reductase (NarG) and the assimilatory nitrate reductase (NasC), the latter of which is active during both aerobic and anaerobic nitrate assimilation. Bioinformatic analysis suggests that the potential for this previously unrecognized role for NarJ in functional maturation of other cytoplasmic molybdenum-dependent nitrate reductases may be phylogenetically widespread as many bacteria contain both Nar and Nas systems.
由于在农业土壤上持续使用无机肥料，硝酸盐在许多环境中都可被微生物获得，许多细菌和古菌谱系都有表达呼吸（Nar）和同化（Nas）硝酸盐还原酶的能力，以利用这种丰富的呼吸底物和营养物质进行生长。在这里，我们表明，在反硝化细菌脱氮副球菌中，NarJ 作为厌氧呼吸硝酸盐还原酶（NarG）和同化硝酸盐还原酶（NasC）的伴侣，后者在有氧和厌氧硝酸盐同化过程中都具有活性。生物信息学分析表明，NarJ 在其他细胞质钼依赖型硝酸盐还原酶的功能成熟中发挥这种以前未被认识到的作用的潜力可能在系统发育上广泛存在，因为许多细菌都同时含有 Nar 和 Nas 系统。
