Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Proteins. 2024 Mar;92(3):370-383. doi: 10.1002/prot.26627. Epub 2023 Nov 1.
The thioredoxin system is a ubiquitous oxidoreductase system consisting of the enzyme thioredoxin reductase, the protein thioredoxin, and the cofactor nicotinamide adenine dinucleotide phosphate. The system has been comprehensively studied from many organisms, such as Escherichia coli; however, structural and functional analysis of this system from psychrophilic bacteria has not been as extensive. In this study, the thioredoxin system proteins of a psychrophilic bacterium, Colwellia psychrerythraea, were characterized using biophysical and biochemical techniques. Analysis of the complete genome sequence of the C. psychrerythraea thioredoxin system suggested the presence of a putative thioredoxin reductase and at least three thioredoxin. In this study, these identified putative thioredoxin system components were cloned, overexpressed, purified, and characterized. Our studies have indicated that the thioredoxin system proteins from E. coli were more stable than those from C. psychrerythraea. Consistent with these results, kinetic assays indicated that the thioredoxin reductase from E. coli had a higher optimal temperature than that from C. psychrerythraea.
硫氧还蛋白系统是一种普遍存在的氧化还原酶系统，由酶硫氧还蛋白还原酶、蛋白硫氧还蛋白和辅酶烟酰胺腺嘌呤二核苷酸磷酸组成。该系统已从许多生物体（如大肠杆菌）中进行了全面研究；然而，对嗜冷菌中该系统的结构和功能分析尚未广泛开展。在这项研究中，使用生物物理和生化技术对嗜冷菌 Colwellia psychrerythraea 的硫氧还蛋白系统蛋白进行了表征。对 C. psychrerythraea 硫氧还蛋白系统的完整基因组序列分析表明，存在一个推定的硫氧还蛋白还原酶和至少三种硫氧还蛋白。在这项研究中，鉴定出的这些假定的硫氧还蛋白系统成分被克隆、过表达、纯化和表征。我们的研究表明，来自大肠杆菌的硫氧还蛋白系统蛋白比来自 C. psychrerythraea 的蛋白更稳定。与这些结果一致，动力学测定表明，来自大肠杆菌的硫氧还蛋白还原酶的最适温度高于来自 C. psychrerythraea 的硫氧还蛋白还原酶。
