Division of Biochemistry, Department of Chemistry, Vienna Institute of BioTechnology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
Departments of Life Sciences.
J Biol Chem. 2013 Sep 20;288(38):27181-27199. doi: 10.1074/jbc.M113.477067. Epub 2013 Aug 5.
Reconstructing the phylogenetic relationships of the main evolutionary lines of the mammalian peroxidases lactoperoxidase and myeloperoxidase revealed the presence of novel bacterial heme peroxidase subfamilies. Here, for the first time, an ancestral bacterial heme peroxidase is shown to possess a very high bromide oxidation activity (besides conventional peroxidase activity). The recombinant protein allowed monitoring of the autocatalytic peroxide-driven formation of covalent heme to protein bonds. Thereby, the high spin ferric rhombic heme spectrum became similar to lactoperoxidase, the standard reduction potential of the Fe(III)/Fe(II) couple shifted to more positive values (-145 ± 10 mV at pH 7), and the conformational and thermal stability of the protein increased significantly. We discuss structure-function relationships of this new peroxidase in relation to its mammalian counterparts and ask for its putative physiological role.
重建哺乳动物过氧化物酶乳过氧化物酶和髓过氧化物酶主要进化线的系统发育关系，揭示了新型细菌血红素过氧化物酶亚家族的存在。在这里，首次表明一种古老的细菌血红素过氧化物酶具有非常高的溴化物氧化活性（除了传统的过氧化物酶活性之外）。重组蛋白允许监测自催化过氧化物驱动的共价血红素与蛋白质键的形成。由此，高自旋菱形高铁血红素谱变得类似于乳过氧化物酶，Fe(III)/Fe(II) 对的标准还原电位向更正的数值移动（在 pH 7 时为-145±10 mV），并且蛋白质的构象和热稳定性显著增加。我们讨论了这种新型过氧化物酶与其哺乳动物对应物的结构-功能关系，并询问了其可能的生理作用。
