Bacteria capture iron from heme by keeping tetrapyrrol skeleton intact
Bacteria capture iron from heme by keeping tetrapyrrol skeleton intact
复制标题
DOI：
10.1073/pnas.0903842106
复制
发表时间：
2009-07-14
影响因子：
11.1
通讯作者：
Wandersman, Cecile
中科院分区：
文献类型：
--
作者：
Letoffe, Sylvie;Heuck, Gesine;Wandersman, Cecile
由于血红素是脊椎动物中主要的含铁分子，因此使用血红素结合铁的能力是细菌病原体成功感染的决定性因素。直到今天，所有已知的从血红素中提取铁的酶都是通过四吡咯骨架的破裂来实现的。在这里，我们确定了2大肠杆菌旁系同源，YfeX和EfeB，没有任何以前已知的生理功能。YfeX和EfeB促进铁提取血红素保留四吡咯环完整。这种新的酶促反应对应于血红素的去铁螯合作用。YfeX和EfeB是唯一能够从外源血红素源向大肠杆菌提供铁的蛋白质。杆菌YfeX位于细胞质中。EfeB是周质的，并且能够在不存在任何血红素渗透酶的情况下从周质中的血红素提取铁和吸收铁。YfeX和EfeB在细菌中广泛存在且高度保守。我们认为它们的生理功能是从血红素中回收铁。
Because heme is a major iron-containing molecule in vertebrates, the ability to use heme-bound iron is a determining factor in successful infection by bacterial pathogens. Until today, all known enzymes performing iron extraction from heme did so through the rupture of the tetrapyrrol skeleton. Here, we identified 2 Escherichia coli paralogs, YfeX and EfeB, without any previously known physiological functions. YfeX and EfeB promote iron extraction from heme preserving the tetrapyrrol ring intact. This novel enzymatic reaction corresponds to the deferrochelation of the heme. YfeX and EfeB are the sole proteins able to provide iron from exogenous heme sources to E. coli. YfeX is located in the cytoplasm. EfeB is periplasmic and enables iron extraction from heme in the periplasm and iron uptake in the absence of any heme permease. YfeX and EfeB are widespread and highly conserved in bacteria. We propose that their physiological function is to retrieve iron from heme.