Salmonella is a well-known food-borne pathogen causing disease in humans and animals worldwide. Peptidyl-prolyl isomerases (PPIases) catalyse the cis-trans isomerisation of prolyl bound, which is a slow and rate-limiting step of protein folding. Here, we present the biochemical and molecular characterisation of a novel multi-domain parvulin-type, PPIases-C from the pathogenic bacteria Salmonella Typhimurium, annotated as rPpiC. The recombinant plasmid PpiC_pET28c was used for protein induction using 1.5 mM concentration of isopropyl-β-D-thiogalactopyranoside at 30 °C. Subsequently, the protein was identified by using the LC-MS technique showing high match score and sequence coverage with available PPIases-C proteins database. Using the succinyl-ala-phe-pro-phe-p nitroanilide as a substrate, Vmax of the enzyme was found to be 0.8187 ± 0.1352 µmoles/min and Km = 1.6014 ± 0.8449 µM, respectively. With this, we conclude that rPpiC protein is an active form of protein from Salmonella Typhimurium and plays an important role in protein folding.

中文翻译：

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鼠伤寒沙门氏菌肽基-脯氨酰顺反异构酶 C (PPIase C) 在蛋白质折叠中起重要作用，以维持蛋白质结构

沙门氏菌是一种众所周知的食源性病原体，可导致全世界人类和动物疾病。肽基-脯氨酰异构酶 (PPIases) 催化脯氨酰结合的顺反异构化，这是蛋白质折叠的缓慢和限速步骤。在这里，我们展示了来自病原菌鼠伤寒沙门氏菌的新型多域小蛋白型 PPIases-C 的生化和分子表征，注释为 rPpiC。重组质粒 PpiC_pET28c 用于在 30°C 下使用 1.5 mM 浓度的异丙基-β-D-硫代吡喃半乳糖苷进行蛋白质诱导。随后，通过使用 LC-MS 技术鉴定了蛋白质，该技术显示出与可用 PPIases-C 蛋白质数据库的高匹配分数和序列覆盖率。使用 succinyl-ala-phe-pro-phe-p nitroanilide 作为底物，发现该酶的 Vmax 为 0.8187 ± 0。1352 µmoles/min 和 Km = 1.6014 ± 0.8449 µM，分别。据此，我们得出结论，rPpiC 蛋白是来自鼠伤寒沙门氏菌的一种活性蛋白，在蛋白折叠中起重要作用。