To characterize a pyrazinamidase from non-pathogen Pseudonocardia carboxydivorans. A pyrazinamidase gene pncA encoding a 23-kDa protein PncA-Pse from P. carboxydivorans was over-expressed in Escherichia coli and characterized. This PncA-Pse can convert both pyrazinamide and nicotinamide efficiently with the optimal pH and temperature of pH 8.5 and 45 °C, respectively. Although ferrous iron and manganese were detected in PncA-Pse, the enzymatic activity is not affected by EDTA with the final concentration of 10 mM. Moreover, the enzymatic activity was not significantly affected with the addition of several metal ions, respectively. Based on the structure modeling, the 61st histidine which is associated with the metal binding, was mutated into alanine to get mutant H61A. No activity, iron and manganese were detected for H61A, which implies that PncA-Pse is a metal enzyme with resistance of the metal ion chelator EDTA, which is different from the previous reports. This is the first characterized pyrazinamidase from the genus Pseudonocardia, a non-pathogen.

中文翻译：

---

来自非病原体 Pseudonocardia carboxydivorans 的 EDTA 抗性吡嗪酰胺酶

表征来自非病原体 Pseudonocardia carboxydivorans 的吡嗪酰胺酶。编码来自 P. carboxydivorans 的 23 kDa 蛋白 PncA-Pse 的吡嗪酰胺酶基因 pncA 在大肠杆菌中过度表达并进行了表征。这种 PncA-Pse 可以有效地转化吡嗪酰胺和烟酰胺，最佳 pH 值和温度分别为 8.5 和 45 °C。虽然在 PncA-Pse 中检测到亚铁和锰，但酶活性不受终浓度为 10 mM 的 EDTA 的影响。此外，分别加入几种金属离子对酶活性没有显着影响。基于结构模型，与金属结合的第61组氨酸突变为丙氨酸以获得突变体H61A。没有检测到 H61A 的活性，铁和锰，这意味着 PncA-Pse 是一种对金属离子螯合剂 EDTA 具有抗性的金属酶，这与之前的报道不同。这是来自非病原体 Pseudonocardia 属的第一个表征的吡嗪酰胺酶。