Comparative Proteomic and Metabolomic Analysis of Staphylococcus warneri SG1 Cultured in the Presence and Absence of Butanol

The complete genome of the solvent tolerant Staphylococcus warneri SG1 was recently published. This Gram-positive bacterium is tolerant to a large spectrum of organic solvents including short-chain alcohols, alkanes, esters and cyclic aromatic compounds. In this study, we applied a two-dimensional liquid chromatography (2D-LC) mass spectrometry (MS) shotgun approach, in combination with quantitative 2-MEGA (dimethylation after guanidination) isotopic labeling, to compare the proteomes of SG1 grown under butanol-free and butanol-challenged conditions. In total, 1585 unique proteins (representing 65% of the predicted open reading frames) were identified, covering all major metabolic pathways. Of the 967 quantifiable proteins by 2-MEGA labeling, 260 were differentially expressed by at least 1.5-fold. These proteins are involved in energy metabolism, oxidative stress response, lipid and cell envelope biogenesis, or have chaperone functions. We also applied differential isotope labeling LC-MS to probe metabolite changes in key metabolic pathways upon butanol stress. This is the first comprehensive proteomic and metabolomic study of S. warneri SG1 and presents an important step toward understanding its physiology and mechanism of solvent tolerance.

耐溶剂沃氏葡萄球菌（Staphylococcus warneri）SG1的完整基因组已于近期发表。该革兰氏阳性菌可耐受多种有机溶剂，涵盖短链醇、烷烃、酯类及环状芳香族化合物。本研究采用二维液相色谱（two-dimensional liquid chromatography, 2D-LC）-质谱（mass spectrometry, MS）鸟枪法蛋白质组学分析策略，并结合定量2-MEGA（胍基化后二甲基化）同位素标记技术，对比了在无丁醇胁迫与丁醇胁迫条件下培养的SG1的蛋白质组。共计鉴定到1585种独特蛋白质，占预测开放阅读框（open reading frames, ORF）的65%，覆盖所有主要代谢通路。在通过2-MEGA标记实现定量的967种蛋白质中，有260种蛋白质的表达量差异至少达1.5倍。这些蛋白质参与能量代谢、氧化应激响应、脂质与细胞被膜生物发生过程，或发挥分子伴侣功能。本研究还采用差异同位素标记LC-MS技术，探究了丁醇胁迫下关键代谢通路中的代谢物变化情况。本研究是针对沃氏葡萄球菌SG1的首个综合性蛋白质组学与代谢组学研究，为解析其生理特性与溶剂耐受机制迈出了重要一步。