The 1-cyseine peroxiredoxin (Prx6) is an importantly antioxidant enzyme that protects cells from oxidative damage caused by excessive production of reactive oxygen species (ROS). In this study, we described the molecular characteristics of the noble scallop Chlamys nobilis peroxiredoxin 6 (designed as CnPrx6), immune responses and DNA protection activity of the recombinant protein. The complete ORF (696 bp) of CnPrx6 encoded a polypeptide (25.5 kDa) of 231 amino acids, harboring a conserved peroxidase catalytic center (⁴¹PVCTTE⁴⁶) and the catalytic triads putatively involved in peroxidase and phospholipase A2 activities. The deduced amino acid sequence of CnPrx6 shared a relatively high amino acid sequence similarity (more than 50%). The qRT-PCR revealed that the CnPrx6 mRNA was constitutively expressed in all examined tissues, with the highest expression observed in adductor. Upon immunological challenge with Vibrio parahaemolyticus, lipopolysaccharides (LPS) and polyinosinic-polycytidylic acid (Poly I:C), the expression level of CnPrx6 mRNA was significantly up-regulated (P < 0.05). Furthermore, there was a significant difference (P < 0.05) in the expression level of CnPrx6 between golden and brown scallops. The purified recombinant CnPrx6 protein protected the supercoiled plasmid DNA from metal-catalyzed ROS damage. Taken together, these results indicated that the CnPrx6 may play an important role in modulating immune responses and minimizing DNA damage in noble scallop Chlamys nobilis.

1-半胱氨酸过氧化物酶（Prx6）是一种重要的抗氧化酶，可保护细胞免受因活性氧（ROS）过量产生而引起的氧化损伤。在这项研究中，我们描述了贵族扇贝Chlamys nobilis peroxiredoxin 6（设计为CnPrx6）的分子特征，重组蛋白的免疫应答和DNA保护活性。CnPrx6的完整ORF（696 bp）编码了一个231个氨基酸的多肽（25.5 kDa），具有保守的过氧化物酶催化中心（⁴¹ PVCTTE ⁴⁶）和催化的三联体，它们可能参与了过氧化物酶和磷脂酶A2的活性。推导的CnPrx6氨基酸序列具有较高的氨基酸序列相似性（超过50％）。qRT-PCR显示CnPrx6 mRNA在所有检查的组织中组成性表达，在内含子中观察到最高表达。副溶血性弧菌，脂多糖（LPS）和聚肌苷酸-聚胞苷酸（Poly I：C）进行免疫学攻击后，CnPrx6 mRNA的表达水平显着上调（P  <0.05）。此外，金色和棕色扇贝之间 的CnPrx6表达水平存在显着差异（P <0.05）。纯化的重组CnPrx6蛋白质保护超螺旋质粒DNA免受金属催化的ROS损伤。综上所述，这些结果表明CnPrx6可能在调节高贵扇贝Chlamys nobilis的免疫反应和最小化DNA损伤中起重要作用。