State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; School of Life Science, Hubei University, Wuhan 430062, PR China.
State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei University, Wuhan 430062, PR China; School of Life Science, Hubei University, Wuhan 430062, PR China.
J Proteomics. 2024 Feb 10;292:105047. doi: 10.1016/j.jprot.2023.105047. Epub 2023 Nov 18.
The wide distribution of laccases in nature makes them involved in different biological processes. However, little information is known about how laccase participates in the defense machinery of bacteria against oxidative stress. The present study aimed to elucidate the oxidative stress response mechanism of Bacillus pumilus ZB1 and the functional role of bacterial laccase in stress defense. The oxidative stress caused by methyl methanesulfonate (MMS) significantly induced laccase activity and its transcript level. The morphological analysis revealed that the defense of B. pumilus ZB1 against oxidative stress was activated. Based on the proteomic study, 114 differentially expressed proteins (DEPs) were up-regulated and 79 DEPs were down-regulated. In COG analysis, 66.40% DEPs were classified into the category "Metabolism". We confirmed that laccase was up-regulated in response to MMS stress and its functional annotation was related to "Secondary metabolites biosynthesis, transport and catabolism". Based on protein-protein interaction prediction, two up-regulated DEPs (YcnJ and GabP) showed interaction with laccase and contributed to the formation of laccase stability and adaptability. The overexpressed laccase might improve the antioxidative property of B. pumilus ZB1. These findings provide an insight and the guidelines for better exploitation of bioremediation using bacterial laccase. SIGNIFICANCE: Bacillus pumilus is a gram-positive bacterium that has the potential for many applications, such as bioremediation. The expression of bacterial laccase is significantly influenced by oxidative stress, while the underlying mechanism of laccase overexpression in bacteria has not been fully studied. Elucidation of the biological process may benefit the bioremediation using bacteria in the future. In this study, the differentially expressed proteins were analyzed using a TMT-labeling proteomic approach when B. pumilus was treated with methyl methanesulfonate (MMS). Reactive oxygen species induced by MMS activated the secondary metabolites biosynthesis, transport, and catabolism in B. pumilus, including laccase overexpression. Moreover, the simultaneously up-regulated YcnJ and GabP may benefit the synthesis and the stability of laccase, then improve the antioxidative property of B. pumilus against environmental stress. Our findings advance the understanding of the adaptive mechanism of B. pumilus to environmental conditions.
漆酶广泛存在于自然界中，参与多种生物学过程。然而，关于漆酶如何参与细菌的氧化应激防御机制知之甚少。本研究旨在阐明短芽孢杆菌 ZB1 的氧化应激响应机制以及细菌漆酶在应激防御中的功能作用。甲磺酸甲酯（MMS）引起的氧化应激显著诱导了漆酶活性及其转录水平的增加。形态分析表明，短芽孢杆菌 ZB1 对氧化应激的防御被激活。基于蛋白质组学研究，发现 114 个差异表达蛋白（DEPs）上调，79 个 DEPs 下调。在 COG 分析中，66.40%的 DEPs 被归类为“代谢”。我们证实，漆酶在 MMS 应激下上调，其功能注释与“次生代谢物生物合成、转运和分解”有关。基于蛋白质-蛋白质相互作用预测，两个上调的 DEPs（YcnJ 和 GabP）与漆酶相互作用，有助于漆酶稳定性和适应性的形成。过表达的漆酶可能提高了短芽孢杆菌 ZB1 的抗氧化能力。这些发现为更好地利用细菌漆酶进行生物修复提供了深入的了解和指导。意义：短芽孢杆菌是一种革兰氏阳性菌，具有许多应用潜力，如生物修复。细菌漆酶的表达受氧化应激的显著影响，但细菌中漆酶过表达的潜在机制尚未得到充分研究。阐明这一生物学过程可能有助于未来利用细菌进行生物修复。在这项研究中，当短芽孢杆菌用甲基甲磺酸酯（MMS）处理时，使用 TMT 标记蛋白质组学方法分析差异表达蛋白。MMS 诱导的活性氧激活了短芽孢杆菌中的次生代谢物生物合成、转运和分解，包括漆酶的过表达。此外，同时上调的 YcnJ 和 GabP 可能有利于漆酶的合成和稳定性，从而提高短芽孢杆菌对环境胁迫的抗氧化能力。我们的研究结果推进了对短芽孢杆菌适应环境条件的机制的理解。
