Heme Binding to HupZ with a C-Terminal Tag from Group A Streptococcus.
Heme Binding to HupZ with a C-Terminal Tag from Group A Streptococcus.
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DOI：
10.3390/molecules26030549
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发表时间：
2021-01-21
期刊：
影响因子：
--
通讯作者：
Liu A
中科院分区：
文献类型：
--
作者：
Traore ES;Li J;Chiura T;Geng J;Sachla AJ;Yoshimoto F;Eichenbaum Z;Davis I;Mak PJ;Liu A
HupZ是A组链球菌血红素获取和利用途径中的一种预期的血红素降解酶。分离的含有C端V5-His6标签的HupZ蛋白显示出弱的血红素降解活性。在这里，我们通过生化、诱变、蛋白质四级结构、UV-Vis、EPR和共振拉曼光谱对HupZ-V5-His6蛋白进行了重新研究和表征。结果表明，铁血红素-蛋白质复合体没有显示预期的铁EPR信号，血红素与HupZ结合触发了更高低聚态的形成。我们发现，血红素与HupZ的结合是一个O2依赖的过程。HupZ序列中的单个组氨酸残基His111不与亚铁血红素结合，也不参与对亚铁血红素的弱降解活性。我们的结果不利于血红素加氧酶的分配，因为血红素结合缓慢，并且新发现的微弱的血红素降解活性与His6-Tag有关。综上所述，数据表明，该蛋白通过其His6标签与血红素结合，导致血红素诱导的高阶低聚结构和血红素堆积。这项工作强调了在研究血红素利用蛋白期间解释实验观察时考虑外源标签的重要性。
HupZ is an expected heme degrading enzyme in the heme acquisition and utilization pathway in Group A Streptococcus. The isolated HupZ protein containing a C-terminal V5-His6 tag exhibits a weak heme degradation activity. Here, we revisited and characterized the HupZ-V5-His6 protein via biochemical, mutagenesis, protein quaternary structure, UV–vis, EPR, and resonance Raman spectroscopies. The results show that the ferric heme-protein complex did not display an expected ferric EPR signal and that heme binding to HupZ triggered the formation of higher oligomeric states. We found that heme binding to HupZ was an O2-dependent process. The single histidine residue in the HupZ sequence, His111, did not bind to the ferric heme, nor was it involved with the weak heme-degradation activity. Our results do not favor the heme oxygenase assignment because of the slow binding of heme and the newly discovered association of the weak heme degradation activity with the His6-tag. Altogether, the data suggest that the protein binds heme by its His6-tag, resulting in a heme-induced higher-order oligomeric structure and heme stacking. This work emphasizes the importance of considering exogenous tags when interpreting experimental observations during the study of heme utilization proteins.
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DOI：
10.1007/978-0-387-73960-1_3
发表时间：
2008-01-01
期刊：
HOT TOPICS IN INFECTION AND IMMUNITY IN CHILDREN IV
影响因子：
--
作者：
Cunningham, Madeleine W.
通讯作者：
Cunningham, Madeleine W.
影响因子：
3.1
作者：
Eichenbaum, Z;Muller, E;Scott, JR
通讯作者：
Scott, JR
影响因子：
3.1
作者：
Lei, BF;Liu, MY;Musser, JM
通讯作者：
Musser, JM
影响因子：
2.9
作者：
Chen, Yan;Naik, Sunil G.;Liu, Aimin
通讯作者：
Liu, Aimin
DOI：
10.1107/s0907444909042073
发表时间：
2010-01
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Chen VB;Arendall WB 3rd;Headd JJ;Keedy DA;Immormino RM;Kapral GJ;Murray LW;Richardson JS;Richardson DC
通讯作者：
Richardson DC