Vázquez-Torres Andrés, Bäumler Andreas J
Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States; Veterans Affairs Eastern Colorado Health Care System, Denver, CO, United States.
Department of Medical Microbiology and Immunology, University of California Davis, School of Medicine, Davis, CA, United States.
Curr Opin Microbiol. 2016 Feb;29:1-8. doi: 10.1016/j.mib.2015.09.002. Epub 2015 Sep 29.
The electrochemical gradient that ensues from the enzymatic activity of cytochromes such as nitrate reductase, nitric oxide reductase, and quinol oxidase contributes to the bioenergetics of the bacterial cell. Reduction of nitrogen oxides by bacterial pathogens can, however, be uncoupled from proton translocation and biosynthesis of ATP or NH4(+), but still linked to quinol and NADH oxidation. Ancestral nitric oxide reductases, as well as cytochrome c oxidases and quinol bo oxidases evolved from the former, are capable of binding and detoxifying nitric oxide to nitrous oxide. The NO-metabolizing activity associated with these cytochromes can be a sizable source of antinitrosative defense in bacteria during their associations with host cells. Nitrosylation of terminal cytochromes arrests respiration, reprograms bacterial metabolism, stimulates antioxidant defenses and alters antibiotic cytotoxicity. Collectively, the bioenergetics and regulation of redox homeostasis that accompanies the utilization of nitrogen oxides and detoxification of nitric oxide by cytochromes of the electron transport chain increases fitness of many Gram-positive and -negative pathogens during their associations with invertebrate and vertebrate hosts.
由硝酸盐还原酶、一氧化氮还原酶和喹啉氧化酶等细胞色素的酶活性所产生的电化学梯度有助于细菌细胞的生物能量学。然而，细菌病原体对氮氧化物的还原作用可能与质子转运以及ATP或NH4(+)的生物合成解偶联，但仍与喹啉和NADH氧化相关。祖先一氧化氮还原酶以及由前者进化而来的细胞色素c氧化酶和喹啉bo氧化酶能够将一氧化氮结合并解毒为一氧化二氮。与这些细胞色素相关的NO代谢活性在细菌与宿主细胞相互作用期间可能是细菌抗亚硝化防御的一个重要来源。末端细胞色素的亚硝化作用会阻止呼吸作用、重新编程细菌代谢、刺激抗氧化防御并改变抗生素细胞毒性。总的来说，电子传递链细胞色素利用氮氧化物和一氧化氮解毒过程中伴随的生物能量学和氧化还原稳态调节增加了许多革兰氏阳性和阴性病原体在与无脊椎动物和脊椎动物宿主相互作用期间的适应性。
