Stork Tina, Laxa Miriam, Dietz Marina S, Dietz Karl-Josef
Biochemistry and Physiology of Plants, Faculty of Biology, W5-134, Bielefeld University, 33501, Bielefeld, Germany.
Arch Microbiol. 2009 Feb;191(2):141-51. doi: 10.1007/s00203-008-0438-7. Epub 2008 Oct 31.
The genome of Synechococcus elongatus PCC 7942 encodes six peroxiredoxins (Prx). Single genes are present each for a 1-Cys Prx and a 2-Cys Prx, while four genes code for PrxQ-like proteins (prxQ-A1, -A2, -A3 and B). Their transcript accumulation varies with growth conditions in a gene-specific manner (Stork et al. in J Exp Bot 56:3193-3206, 2005). To address their functional properties, members of the prx gene family were produced as recombinant proteins and analysed for their peroxide detoxification capacity and quaternary structure by size exclusion chromatography. Independent of the reduction state, the 2-Cys Prx separated as oligomer, the 1-Cys Prx as dimer and the PrxQ-A1 as monomer. PrxQ-A2 was inactive in our assays, 1-Cys Prx activity was unaffected by addition of TrxA, while all others were stimulated to a variable extent by addition of E. coli thioredoxin. Sensitivity towards cumene hydroperoxide treatment of E. coli BL21 cells expressing the cyanobacterial PrxQ-A1 to A3 proteins was greatly reduced, while expression of the other Prx had no effect. The study shows differentiation of Prx functions in S. elongatus PCC 7942 which is discussed in relation to potential roles in site- and stress-specific defence.
聚球藻PCC 7942的基因组编码六种过氧化物还原酶（Prx）。单基因分别存在于一个1-Cys Prx和一个2-Cys Prx中，而四个基因编码PrxQ样蛋白（prxQ-A1、-A2、-A3和B）。它们的转录积累以基因特异性方式随生长条件而变化（Stork等人，《实验植物学杂志》56:3193 - 3206，2005年）。为了研究它们的功能特性，prx基因家族的成员被制备为重组蛋白，并通过尺寸排阻色谱分析它们的过氧化物解毒能力和四级结构。与还原状态无关，2-Cys Prx以寡聚体形式分离，1-Cys Prx以二聚体形式分离，PrxQ-A1以单体形式分离。PrxQ-A2在我们的实验中无活性，1-Cys Prx的活性不受TrxA添加的影响，而其他所有蛋白在添加大肠杆菌硫氧还蛋白后受到不同程度的刺激。表达蓝藻PrxQ-A1至A3蛋白的大肠杆菌BL21细胞对氢过氧化异丙苯处理的敏感性大大降低，而其他Prx的表达则没有影响。该研究表明了聚球藻PCC 7942中Prx功能的分化，并结合其在特定部位和应激特异性防御中的潜在作用进行了讨论。
