金黄色葡萄球菌是一种机会性病原体,由于其耐药性的增加,已成为主要的公共卫生威胁。金黄色葡萄球菌由于其能量代谢的可塑性而表现出明显的适应不同生态位的能力。在这项工作中,我们研究了金黄色葡萄球菌的能量代谢,专注于替代NADH:醌氧化还原酶,NDH-2s。金黄色葡萄球菌存在两个编码NDH-2s的基因(NDH-2A和NDH-2B),并且缺乏编码复合物I的基因,典型的呼吸NADH:醌氧化还原酶。这一观察使得NDH-2s的作用对于NAD+的再生至关重要,因此,新陈代谢的进展。我们的研究涉及NDH-2B的全面生化特征以及NDH-2A和NDH-2B的细胞作用的探索。利用敲除突变体(Δndh-2a和Δndh-2b)。我们证明NDH-2B使用NADPH代替NADH,在NADPH存在下不建立电荷转移复合物,并且其被该底物还原是催化速率限制步骤。在NDH-2B的情况下,黄素的减少本质上是缓慢的,我们建议在NADP+和FADH2之间建立电荷转移复合物,正如之前在NDH-2A中观察到的那样,减缓醌的还原,因此,防止活性氧的过量产生,这可能是不必要的。此外,我们观察到缺乏NDH-2A或NDH-2B会影响细胞生长,volume,不同的划分。这些酶的缺乏导致不同的代谢表型,强调每个NDH-2在能量代谢中的独特细胞作用。重要金黄色葡萄球菌是一种机会致病菌,由于其耐药性的增加,在临床医学中构成了全球性的挑战。出于这个原因,探索和理解其抵抗背后的机制至关重要,以及基本的生物学特征,如能量代谢和各自的球员,让金黄色葡萄球菌生活和生存。尽管它作为病原体很突出,金黄色葡萄球菌的能量代谢仍未充分开发,其呼吸酶经常逃避彻底的调查。金黄色葡萄球菌的生物能量可塑性通过其使用不同呼吸酶的能力来说明,其中两项在本研究中进行了调查。了解金黄色葡萄球菌对生物能量挑战的代谢适应策略可能会为治疗方法的设计铺平道路,这些治疗方法会干扰病原体侵入其宿主内的不同生态位时成功适应的能力。
Staphylococcus aureus is an opportunistic pathogen that has emerged as a major public health threat due to the increased incidence of its drug resistance. S. aureus presents a remarkable capacity to adapt to different niches due to the plasticity of its energy metabolism. In this work, we investigated the energy metabolism of S. aureus, focusing on the alternative NADH:quinone oxidoreductases, NDH-2s. S. aureus presents two genes encoding NDH-2s (NDH-2A and NDH-2B) and lacks genes coding for Complex I, the canonical respiratory NADH:quinone oxidoreductase. This observation makes the action of NDH-2s crucial for the regeneration of NAD+ and, consequently, for the progression of metabolism. Our study involved the comprehensive biochemical characterization of NDH-2B and the exploration of the cellular roles of NDH-2A and NDH-2B, utilizing knockout mutants (Δndh-2a and Δndh-2b). We show that NDH-2B uses NADPH instead of NADH, does not establish a charge-transfer complex in the presence of NADPH, and its reduction by this substrate is the catalytic rate-limiting step. In the case of NDH-2B, the reduction of the flavin is inherently slow, and we suggest the establishment of a charge transfer complex between
NADP+ and FADH2, as previously observed for NDH-2A, to slow down quinone reduction and, consequently, prevent the overproduction of reactive oxygen species, which is potentially unnecessary. Furthermore, we observed that the lack of NDH-2A or NDH-2B impacts cell growth, volume, and division differently. The absence of these enzymes results in distinct metabolic phenotypes, emphasizing the unique cellular roles of each NDH-2 in energy metabolism.IMPORTANCEStaphylococcus aureus is an opportunistic pathogen, posing a global challenge in clinical medicine due to the increased incidence of its drug resistance. For this reason, it is essential to explore and understand the mechanisms behind its resistance, as well as the fundamental biological features such as energy metabolism and the respective players that allow S. aureus to live and survive. Despite its prominence as a pathogen, the energy metabolism of S. aureus remains underexplored, with its respiratory enzymes often escaping thorough investigation. S. aureus bioenergetic plasticity is illustrated by its ability to use different respiratory enzymes, two of which are investigated in the present study. Understanding the metabolic adaptation strategies of S. aureus to bioenergetic challenges may pave the way for the design of therapeutic approaches that interfere with the ability of the pathogen to successfully adapt when it invades different niches within its host.