An outer membrane protein A (OmpA) from Acinetobacter sp. strain SA01 was identified and characterized in-depth based on the structural and functional characteristics already known of its homologues. In silico structural studies showed that this protein can be a slow porin, binds to peptidoglycan, and exhibits emulsifying properties. Characterization of the recombinant SA01-OmpA, based on its emulsifying properties, represented its promising potentials in biotechnology. Also, the presence of SA01-OmpA in outer membrane vesicles (OMV) and biofilm showed that this protein, like its homologues in Acinetobacter baumannii, can be secreted into the extracellular environment through OMVs and play a role in the formation of biofilm. After ensuring the correct selection of the protein of interest, the role of oxidative stress induced by cell nutritional parameters (utilization of specific carbon sources) on the expression level of OmpA was carefully studied. For this purpose, the oxidative stress level of SA01 cell cultures in the presence of three nonrelevant carbon sources (sodium acetate, ethanol, and phenol) was examined under each condition. High expression of SA01-OmpA in ethanol- and phenol-fed cells with higher levels of oxidative stress than acetate suggested that oxidative stress could be a substantial factor in the regulation of SA01-OmpA expression. The significant association of SA01-OmpA expression with the levels of oxidative stress induced by cadmium and H₂O₂, with oxidative stress-inducing properties and lack of nutritional value, confirmed that the cells tend to harness their capacities with a possible increase in OmpA production. Collectively, this study suggests a homeostasis role for OmpA in Acinetobacter sp. SA01 under oxidative stress besides assuming many other roles hitherto attributed to this protein.

中文翻译：

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不动杆菌属OmpA的新临时功能 应对环境挑战的SA01菌株

不动杆菌属的外膜蛋白A（OmpA）。根据已经知道的同源物的结构和功能特性，对SA01菌株进行了鉴定和深入表征。在计算机上进行的结构研究表明，该蛋白可以是慢孔蛋白，与肽聚糖结合，并具有乳化特性。基于其乳化特性，重组SA01-OmpA的表征代表了其在生物技术中的有前途的潜力。同样，在外膜囊泡（OMV）和生物膜中SA01-OmpA的存在表明该蛋白，就像鲍曼不动杆菌中的同系物一样可以通过OMVs分泌到细胞外环境中，并在生物膜的形成中起作用。在确保正确选择了感兴趣的蛋白质之后，仔细研究了由细胞营养参数（利用特定碳源）诱导的氧化应激对OmpA表达水平的作用。为此目的，在每种条件下检查了在三种不相关碳源（乙酸钠，乙醇和苯酚）存在下SA01细胞培养物的氧化应激水平。SA01-OmpA在乙醇和苯酚喂养的细胞中高表达，其氧化应激水平高于乙酸盐，这表明氧化应激可能是调节SA01-OmpA表达的重要因素。具有氧化应激诱导特性且缺乏营养价值的₂ O ₂证实，细胞倾向于利用其能力，可能增加OmpA的产生。总体而言，这项研究表明OmpA在不动杆菌属中具有稳态作用。SA01在氧化应激下除了承担迄今归因于该蛋白的许多其他作用外。