The Influence of Blue Light and the BlsA Photoreceptor on the Oxidative Stress Resistance Mechanisms of Acinetobacter baumannii.
The Influence of Blue Light and the BlsA Photoreceptor on the Oxidative Stress Resistance Mechanisms of Acinetobacter baumannii.
复制标题
DOI：
10.3389/fcimb.2022.856953
复制
发表时间：
2022
影响因子：
5.7
通讯作者：
Actis LA
中科院分区：
文献类型：
--
作者：
Squire MS;Townsend HA;Actis LA
鲍氏不动杆菌是一种过氧化氢酶阳性革兰氏阴性细菌病原体，可导致受损患者严重感染。在其值得注意的调节机制中，这种微生物通过使用黄素（BLUF）蛋白BlsA的蓝光调节其生活方式。这种蛋白质调节多种细胞过程，包括但不限于运动性、生物膜形成、苯乙酸代谢、铁摄取和过氧化氢酶活性。我们开始确定A。鲍曼不动杆菌调节过氧化氢酶活性和其它响应光的相关氧化应激表型。值得注意的是，因为A。鲍曼不动杆菌ATCC 17978编码四种过氧化氢酶同源物-我们将其称为KatA、KatE、KatE 2和KatG -我们还旨在显示这些酶中的哪一种表现出光依赖性和BlsA依赖性活性。我们的工作不仅提供了深入了解所有四个过氧化氢酶同系物的一般功能和光对这些功能的影响，而且还直接确定KatE作为BlsA调节的酶。我们进一步证明，BlsA对KatE的调节依赖于我们之前证明的调节表面运动所必需的赖氨酸残基。此外，我们表明，BlsA的5个最C-末端残基-以前被认为是BlsA的整体功能的非依赖性和光依赖性的过氧化氢酶和超氧化物歧化酶活性的调节，分别是必要的。我们推测，这些确定的关键残基是必要的BlsA的相互作用与蛋白质的合作伙伴，包括转录调节Fur和BfmR。这些数据一起扩展了对A.鲍曼不动杆菌利用光作为信号来控制对其病理生理学至关重要的氧化应激抗性机制。
Acinetobacter baumannii is a catalase-positive Gram-negative bacterial pathogen that causes severe infections among compromised patients. Among its noteworthy regulatory mechanisms, this microorganism regulates its lifestyle through the blue light using flavin (BLUF) protein BlsA. This protein regulates a diverse set of cellular processes that include, but are not limited to, motility, biofilm formation, phenylacetic acid metabolism, iron uptake, and catalase activity. We set out to determine how A. baumannii regulates catalase activity and other related oxidative stress phenotypes in response to light. Notably, because A. baumannii ATCC 17978 encodes four catalase homologs – which we refer to as KatA, KatE, KatE2, and KatG – we also aimed to show which of these enzymes exhibit light- and BlsA-dependent activity. Our work not only provides insight into the general function of all four catalase homologs and the impact of light on these functions, but also directly identifies KatE as a BlsA-regulated enzyme. We further demonstrate that the regulation of KatE by BlsA is dependent on a lysine residue that we previously demonstrated to be necessary for the regulation of surface motility. Furthermore, we show that BlsA’s five most-C-terminal residues – previously considered dispensable for BlsA’s overall function – are necessary for the light-independent and light-dependent regulation of catalase and superoxide dismutase activities, respectively. We hypothesize that these identified critical residues are necessary for BlsA’s interaction with protein partners including the transcriptional regulators Fur and BfmR. Together these data expand the understanding regarding how A. baumannii uses light as a signal to control oxidative stress resistance mechanisms that are critical for its pathophysiology.