BACKGROUND ClpP is important for bacterial growth and plays an indispensable role in cellular protein quality control systems by refolding or degrading damaged proteins, but the physiological significance of ClpP in Enterococcus faecalis remains obscure. A clpP deletion mutant (△clpP) was constructed using the E. faecalis OG1RF strain to clarify the effect of ClpP on E. faecalis. The global abundance of proteins was determined by a mass spectrometer with tandem mass tag labeling. RESULTS The ΔclpP mutant strain showed impaired growth at 20 °C or 45 °C at 5% NaCl or 2 mM H2O2. The number of surviving ΔclpP mutants decreased after exposure to the high concentration (50× minimal inhibitory concentration) of linezolid or minocycline for 96 h. The ΔclpP mutant strain also demonstrated decreased biofilm formation but increased virulence in a Galleria mellonella model. The mass spectrometry proteomics data indicated that the abundances of 135 proteins changed (111 increased, 24 decreased) in the ΔclpP mutant strain. Among those, the abundances of stress response or virulence relating proteins: FsrA response regulator, gelatinase GelE, regulatory protein Spx (spxA), heat-inducible transcription repressor HrcA, transcriptional regulator CtsR, ATPase/chaperone ClpC, acetyl esterase/lipase, and chaperonin GroEL increased in the ΔclpP mutant strain; however, the abundances of ribosomal protein L4/L1 family protein (rplD), ribosomal protein L7/L12 (rplL2), 50S ribosomal protein L13 (rplM), L18 (rplR), L20 (rplT), 30S ribosomal protein S14 (rpsN2) and S18 (rpsR) all decreased. The abundances of biofilm formation-related adapter protein MecA increased, while the abundances of dihydroorotase (pyrC), orotate phosphoribosyltransferase (pyrE), and orotidine-5'-phosphate decarboxylase (pyrF) all decreased in the ΔclpP mutant strain. CONCLUSION The present study demonstrates that ClpP participates in stress tolerance, biofilm formation, antimicrobial tolerance, and virulence of E. faecalis.

中文翻译：

---

ClpP参与了粪肠球菌的胁迫耐受性，生物膜形成，抗菌耐受性和毒力。

背景技术ClpP对于细菌生长是重要的，并且通过重新折叠或降解受损的蛋白质而在细胞蛋白质质量控​​制系统中起不可缺少的作用，但是ClpP在粪肠球菌中的生理学意义仍然不清楚。使用粪肠球菌OG1RF菌株构建了一个clpP缺失突变体（△clpP），以阐明ClpP对粪肠球菌的影响。通过具有串联质量标签标记的质谱仪确定蛋白质的总体丰度。结果ΔclpP突变菌株在5％NaCl或2 mM H2O2下于20°C或45°C表现出生长受损。暴露于高浓度利奈唑胺或米诺环素（96倍于最小抑制浓度50倍）后，存活的ΔclpP突变体数量减少。ΔclpP突变株还显示出生物膜形成减少，但在Galleria mellonella模型中增加了毒力。质谱蛋白质组学数据表明，ΔclpP突变菌株中135种蛋白质的丰度发生了变化（111种增加，24种减少）。其中包括大量与压力反应或毒力相关的蛋白：FsrA反应调节剂，明胶酶GelE，调节蛋白Spx（spxA），热诱导转录阻遏物HrcA，转录调节剂CtsR，ATPase /分子伴侣ClpC，乙酰酯酶/脂肪酶和伴侣蛋白。在ΔclpP突变株中，GroEL增加；但是，核糖体蛋白L4 / L1家族蛋白（rplD），核糖体蛋白L7 / L12（rplL2），50S核糖体蛋白L13（rplM），L18（rplR），L20（rplT），30S核糖体蛋白S14（rpsN2）丰富。和S18（rpsR）均降低。与生物膜形成相关的衔接蛋白MecA的丰度增加，而ΔclpP突变株中二氢乳清酶（pyrC），乳清酸磷酸核糖基转移酶（pyrE）和Orotidine-5'-磷酸脱羧酶（pyrF）的丰度均下降。结论本研究表明，ClpP参与了粪肠球菌的胁迫耐受性，生物膜形成，抗微生物耐受性和毒力。