Li Hui, Mercer Ryan, Behr Jürgen, Heinzlmeir Stephanie, McMullen Lynn M, Vogel Rudi F, Gänzle Michael G
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
Institute of Quality Standard and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-food Quality and Safety, Ministry of Agriculture, Beijing, China.
Front Microbiol. 2020 Feb 4;11:111. doi: 10.3389/fmicb.2020.00111. eCollection 2020.
The locus of heat resistance (LHR) confers extreme heat resistance in . This study explored the role of the LHR in heat and pressure resistance of , as well as its relationship with protein folding and aggregation . The role of LHR was investigated in MG1655 and the pressure resistant LMM1010 expressing an fusion protein to visualize inclusion bodies by fluorescence microscopy. The expression of proteins by the LHR was determined by proteomic analysis; inclusion bodies of untreated and treated cells were also analyzed by proteomics, and by fluorescent microscopy. In total, 11 proteins of LHR were expressed: sHSP20, ClpK, sHSP, YdfX1 and YdfX2, HdeD, KefB, Trx, PsiE, DegP, and a hypothetical protein. The proteomic analysis of inclusion bodies revealed a differential abundance of proteins related to oxidative stress in strains carrying the LHR. The LHR reduced the presence of inclusion bodies after heat or pressure treatment, indicating that proteins expressed by the LHR prevent protein aggregation, or disaggregate proteins. This phenotype of the LHR was also conferred by expression of a fragment containing only sHSP20, ClpK, and sHSP. The LHR and the fragment encoding only sHSP20, ClpK, and sHSP also enhanced pressure resistance in MG1655 but had no effect on pressure resistance of LMM1010. In conclusion, the LHR confers pressure resistance to some strains of , and reduces protein aggregation. Pressure and heat resistance are also dependent on additional LHR-encoded functions.
耐热位点（LHR）赋予[具体物种]极强的耐热性。本研究探讨了LHR在[具体物种]耐热和耐压中的作用，以及它与蛋白质折叠和聚集的关系。在MG1655和表达融合蛋白以通过荧光显微镜观察包涵体的耐压菌株LMM1010中研究了LHR的作用。通过蛋白质组学分析确定LHR表达的蛋白质；还通过蛋白质组学和荧光显微镜对未处理和处理过的细胞的包涵体进行了分析。总共表达了11种LHR蛋白：小分子热休克蛋白20（sHSP20）、ClpK、小分子热休克蛋白（sHSP）、YdfX1和YdfX2、HdeD、KefB、硫氧还蛋白（Trx）、PsiE、DegP和一种假定蛋白。包涵体的蛋白质组学分析揭示了携带LHR的菌株中与氧化应激相关蛋白质的丰度差异。LHR在热或压力处理后减少了包涵体的存在，表明LHR表达的蛋白质可防止蛋白质聚集或使蛋白质解聚。仅包含sHSP20、ClpK和sHSP的片段的表达也赋予了LHR这种表型。LHR和仅编码sHSP20、ClpK和sHSP的片段也增强了MG1655的耐压性，但对LMM1010的耐压性没有影响。总之，LHR赋予某些[具体物种]菌株耐压性，并减少蛋白质聚集。耐压性和耐热性还取决于LHR编码的其他功能。
