[目的] 研究精氨酸代谢调控蛋白ArgR对嗜热链球菌胞外多糖（EPS）合成的调控作用。[方法] 利用大肠杆菌异源表达嗜热链球菌ArgR蛋白，通过尿素变性-复性和Ni2+亲和层析纯化。采用凝胶电泳迁移（EMSA）和生物膜层干涉（BLI）分析ArgR和eps基因簇中PepsA启动子的相互作用和动力学信息。构建过表达和弱化argR基因菌株，利用苯酚-硫酸法测定其合成EPS差异。[结果] 大肠杆菌异源表达的ArgR为包涵体，使用尿素变性-复性纯化可获得2.95 mg/mL可溶性蛋白；EMSA和BLI结果显示ArgR和启动子PepsA有特异性结合，且结合因解离水平低而稳定；过表达argR基因可显著降低嗜热链球菌EPS合成，而弱化argR基因则提高EPS合成。[结论] 本研究表明ArgR能特异性结合嗜热链球菌eps基因簇启动子，并负调控EPS生物合成。
[Objective] The regulatory effect of arginine regulator ArgR on the biosynthesis of exopolysaccharides (EPS) was studied in Streptococcus thermophilus. [Methods] ArgR from S. thermophilus was heterologously expressed by Escherichia coli, and purified by urea denaturation refolding and Ni2+ affinity chromatography. The interaction and kinetic information between ArgR and eps promoter PepsA were detected by electrophoretic mobility shift assays (EMSA) and biolayer interferometry (BLI). The yield alteration of EPS was determined by phenol-sulfuric acid assay when the gene argR overexpressed or repressed. [Results] Heterologous expression of ArgR was formed inclusion body, and 2.95 mg/mL of soluble protein was achieved by urea denaturation refolding. EMSA and BLI analysis showed that ArgR can specifically bind with the promoter PepsA and their affinity was high because of the low dissociation. Increased expression of argR gene reduced EPS synthesis and the suppression raised. [Conclusion] It is the first time to report that ArgR can specifically bind the promoter of eps gene cluster and negatively regulate EPS synthesis in S. thermophilus.