Hemoglobin binding and catalytic heme extraction by IsdB NEAT domains
Hemoglobin binding and catalytic heme extraction by IsdB NEAT domains
复制标题
IsdB NEAT 结构域的血红蛋白结合和催化血红素提取
DOI：
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Michael E. P. Murphy
中科院分区：
文献类型：
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作者：
C. Bowden;M. Verstraete;L. Eltis;Michael E. P. Murphy
Isd（Iron-regulated surface determinant，铁调节表面决定簇）系统是一种多蛋白转运蛋白，其使细菌金黄色葡萄球菌在人类感染期间从血红蛋白（Hb）摄取铁。在该系统中，IsdB是一种细胞壁锚定的表面蛋白，含有2个NEAT结构域，其中一个结合血红素。IsdB从Hb中快速提取血红素并将其转移到IsdA中以中继到细菌细胞中。使用一系列包含至少一个NEAT结构域的重组IsdB构建体，我们证明了两个结构域都需要以高亲和力（KD = 0.42 ± 0.05 μ M）结合Hb并从Hb中提取血红素。此外，IsdB仅从氧化的metHb中提取血红素，尽管它也结合oxyHb和Hb-CO复合物。在生物血红素传递途径的重建模型中，IsdB催化血红素从metHb转移到IsdA，metHb的Km为0.75 ± 0.07 µ N，kcat为0.22 ± 0.01 s-1。后者与血红素从metHb转移到IsdB作为限速步骤是一致的。与两个NEAT结构域和接头区存在于一个单一的连续多肽，实现了高亲和力Hb结合，快速血红素摄取观察，并进行多次周转血红素提取从metHb和转移到IsdA，代表所有已知的Hb-血红素摄取功能的全长IsdB蛋白。
The Isd (Iron-regulated surface determinant) system is a multi-protein transporter that enables bacterium Staphylococcus aureus to take up iron from hemoglobin (Hb) during human infection. In this system, IsdB is a cell wall-anchored surface protein that contains 2 NEAT domains, one of which binds heme. IsdB rapidly extracts heme from Hb and transfers it to IsdA for relay into the bacterial cell. Using a series of recombinant IsdB constructs which included at least one NEAT domain, we demonstrated that both domains are required to bind Hb with high affinity ( K D = 0.42 ± 0.05 µ M) and to extract heme from Hb. Moreover, IsdB only extracted heme from oxidized metHb although it also bound oxyHb and the Hb-CO complex. In a reconstituted model of the biological heme relay pathway, IsdB catalyzed heme transfer from metHb to IsdA with a K m for metHb of 0.75 ± 0.07 µ N and a k cat of 0.22 ± 0.01 s -1 . The latter is consistent with the transfer of heme from metHb to IsdB as being the rate-limiting step. With both NEAT domains and the linker region present in a single contiguous polypeptide, high affinity Hb binding was achieved, rapid heme uptake was observed, and multiple turnovers of heme extraction from metHb and transfer to IsdA were carried out, representing all known Hb-heme uptake functions of the full-length IsdB protein.
影响因子：
5.5
作者：
Kim, Hwan Keun;DeDent, Andrea;Cheng, Alice G.;McAdow, Molly;Bagnoli, Fabio;Missiakas, Dominique M.;Schneewind, Olaf
通讯作者：
Schneewind, Olaf
DOI：
10.1093/infdis/jit817
发表时间：
2014-06
期刊：
The Journal of infectious diseases
影响因子：
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作者：
Gleb Pishchany;J. Sheldon;C. Dickson;Md Tauqeer Alam;T. Read;D. Gell;D. Heinrichs;Eric P. Skaar
通讯作者：
Gleb Pishchany;J. Sheldon;C. Dickson;Md Tauqeer Alam;T. Read;D. Gell;D. Heinrichs;Eric P. Skaar
金黄色葡萄球菌的生长使用人血红蛋白作为铁源。
DOI：
10.3791/50072
发表时间：
2013
期刊：
Journal of visualized experiments : JoVE
影响因子：
--
作者：
Pishchany,Gleb;Haley,KathrynP;Skaar,EricP
通讯作者：
Skaar,EricP