Schurig-Briccio Lici A, Yano Takahiro, Rubin Harvey, Gennis Robert B
Department of Biochemistry, University of Illinois, 600 S. Mathews Street, Urbana, IL 61801, USA.
Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Biochim Biophys Acta. 2014 Jul;1837(7):954-63. doi: 10.1016/j.bbabio.2014.03.017. Epub 2014 Apr 5.
Methicillin-resistant Staphylococcus aureus (MRSA) is currently one of the principal multiple drug resistant bacterial pathogens causing serious infections, many of which are life-threatening. Consequently, new therapeutic targets are required to combat such infections. In the current work, we explore the type 2 Nicotinamide adenine dinucleotide reduced form (NADH) dehydrogenases (NDH-2s) as possible drug targets and look at the effects of phenothiazines, known to inhibit NDH-2 from Mycobacterium tuberculosis. NDH-2s are monotopic membrane proteins that catalyze the transfer of electrons from NADH via flavin adenine dinucleotide (FAD) to the quinone pool. They are required for maintaining the NADH/Nicotinamide adenine dinucleotide (NAD(+)) redox balance and contribute indirectly to the generation of proton motive force. NDH-2s are not present in mammals, but are the only form of respiratory NADH dehydrogenase in several pathogens, including S. aureus. In this work, the two putative ndh genes present in the S. aureus genome were identified, cloned and expressed, and the proteins were purified and characterized. Phenothiazines were shown to inhibit both of the S. aureus NDH-2s with half maximal inhibitory concentration (IC50) values as low as 8μM. However, evaluating the effects of phenothiazines on whole cells of S. aureus was complicated by the fact that they are also acting as uncouplers of oxidative phosphorylation. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
耐甲氧西林金黄色葡萄球菌（MRSA）是目前导致严重感染的主要多重耐药细菌病原体之一，其中许多感染会危及生命。因此，需要新的治疗靶点来对抗此类感染。在当前的研究中，我们探索了还原型烟酰胺腺嘌呤二核苷酸（NADH）2型脱氢酶（NDH-2s）作为可能的药物靶点，并研究了已知能抑制结核分枝杆菌NDH-2的吩噻嗪类药物的作用。NDH-2s是单一位点膜蛋白，催化电子从NADH通过黄素腺嘌呤二核苷酸（FAD）转移到醌池。它们对于维持NADH/烟酰胺腺嘌呤二核苷酸（NAD(+)）氧化还原平衡是必需的，并间接促进质子动力的产生。NDH-2s在哺乳动物中不存在，但却是包括金黄色葡萄球菌在内的几种病原体中呼吸NADH脱氢酶的唯一形式。在这项研究中，鉴定、克隆并表达了金黄色葡萄球菌基因组中存在的两个假定ndh基因，并对蛋白质进行了纯化和表征。结果表明，吩噻嗪类药物能抑制金黄色葡萄球菌的两种NDH-2s，半数最大抑制浓度（IC50）值低至8μM。然而，评估吩噻嗪类药物对金黄色葡萄球菌全细胞的影响很复杂，因为它们也起到氧化磷酸化解偶联剂的作用。本文是名为“第18届欧洲生物能量学会议”的特刊的一部分。
