Frey Alexander D, Farrés Judith, Bollinger Christian J T, Kallio Pauli T
Institute of Biotechnology, ETH Zürich, CH-8093 Zürich, Switzerland.
Appl Environ Microbiol. 2002 Oct;68(10):4835-40. doi: 10.1128/AEM.68.10.4835-4840.2002.
Escherichia coli MG1655 cells expressing novel bacterial hemoglobin and flavohemoglobin genes from a medium-copy-number plasmid were grown in shake flask cultures under nitrosative and oxidative stress. E. coli cells expressing these proteins display enhanced resistance against the NO(.) releaser sodium nitroprusside (SNP) relative to that of the control strain bearing the parental plasmid. Expression of bacterial hemoglobins originating from Campylobacter jejuni (CHb) and Vitreoscilla sp. (VHb) conferred resistance on SNP-challenged cells. In addition, it has been shown that NO(.) detoxification is also a common feature of flavohemoglobins originating from different taxonomic groups and can be transferred to a heterologous host. These observations have been confirmed in a specific in vitro NO(.) consumption assay. Protein extracts isolated from E. coli strains overexpressing flavohemoglobins consumed authentic NO(.) more readily than protein extracts from the wild-type strain. Oxidative challenge to the cells evoked nonuniform responses from the various cell cultures. Improved oxidative-stress-sustaining properties had also been observed when the flavohemoglobins from E. coli, Klebsiella pneumoniae, Deinococcus radiodurans, and Pseudomonas aeruginosa were expressed in E. coli.
将来自中拷贝数质粒的新型细菌血红蛋白和黄素血红蛋白基因导入大肠杆菌MG1655细胞，并在摇瓶培养中于亚硝化和氧化应激条件下培养。相对于携带亲本质粒的对照菌株，表达这些蛋白质的大肠杆菌细胞对一氧化氮（·NO）释放剂硝普钠（SNP）表现出增强的抗性。源自空肠弯曲菌（CHb）和透明颤菌属（VHb）的细菌血红蛋白的表达赋予了受SNP挑战的细胞抗性。此外，研究表明，一氧化氮（·NO）解毒也是源自不同分类群的黄素血红蛋白的共同特征，并且可以转移到异源宿主中。这些观察结果已在特定的体外一氧化氮（·NO）消耗试验中得到证实。从过表达黄素血红蛋白的大肠杆菌菌株中分离的蛋白质提取物比野生型菌株的蛋白质提取物更容易消耗真实的一氧化氮（·NO）。对细胞的氧化应激挑战引发了各种细胞培养物的不均匀反应。当在大肠杆菌中表达来自大肠杆菌、肺炎克雷伯菌、耐辐射球菌和铜绿假单胞菌的黄素血红蛋白时，也观察到了改善的氧化应激维持特性。
