Crystal structures of EfeB and EfeO in a bacterial siderophore-independent iron transport system
Crystal structures of EfeB and EfeO in a bacterial siderophore-independent iron transport system
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细菌铁载体依赖性铁转运系统中 EfeB 和 EfeO 的晶体结构
DOI：
10.1016/j.bbrc.2022.01.055
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发表时间：
2022
影响因子：
3.1
通讯作者：
Hashimoto Wataru
中科院分区：
文献类型：
--
作者：
Nakatsuji Sakiko;Okumura Kenji;Takase Ryuichi;Watanabe Daisuke;Mikami Bunzo;Hashimoto Wataru
EfeUOB是细菌中不依赖铁载体的铁摄取机制。EfeU、EfeO和EfeB分别是一种渗透酶、一种铁结合或电子转移蛋白和一种过氧化物酶。革兰氏阴性菌，鞘单胞菌。菌株A1在基因组中编码EfeU、EfeO、EfeB和藻酸盐结合蛋白Algp7，这是一种截断的EfeO样蛋白（EfeOII）。典型的EfeO由n端铜氧还蛋白和c端M75肽酶结构域组成。本文详细介绍了细菌EfeB和EfeO的结构和功能。菌株A1 EfeB和大肠杆菌EfeB的晶体结构分别在2.30 Å和1.85 Å分辨率下测定。一个参与氧化酶活性的血红素分子与EfeB的c端Dyp过氧化物酶结构域结合。efeoi的两个结构域通过一个短环连接，一个锌离子结合在c端M75肽酶结构域的四个残基Glu156、Glu159、Asp173和Glu255上。这些残基形成了适合金属结合的四面体几何结构，并且在包括Algp7 （EfeOII）在内的各种EfeO蛋白中具有良好的保守性，尽管金属结合位点（HxxE）被提出在c端M75肽酶结构域。本文首次报道了具有两个结构域的典型EfeO的结构，假设在EfeO c端M75肽酶结构域中存在新的金属结合基序“ExxE-//- d -// /- e”。
EfeUOB is a siderophore-independent iron uptake mechanism in bacteria. EfeU, EfeO, and EfeB are a permease, an iron-binding or electron-transfer protein, and a peroxidase, respectively. A Gram-negative bacterium,Sphingomonassp. strain A1, encodes EfeU, EfeO, EfeB together with alginate-binding protein Algp7, a truncated EfeO-like protein (EfeOII), in the genome. The typical EfeO (EfeOI) consists of N-terminal cupredoxin and C-terminal M75 peptidase domains. Here, we detail the structure and function of bacterial EfeB and EfeO. Crystal structures of strain A1 EfeB andEscherichia coliEfeOIwere determined at 2.30 Å and 1.85 Å resolutions, respectively. A molecule of heme involved in oxidase activity was bound to the C-terminal Dyp peroxidase domain of EfeB. Two domains of EfeOIwere connected by a short loop, and a zinc ion was bound to four residues, Glu156, Glu159, Asp173, and Glu255, in the C-terminal M75 peptidase domain. These residues formed tetrahedron geometry suitable for metal binding and are well conserved among various EfeO proteins including Algp7 (EfeOII), although the metal-binding site (HxxE) is proposed in the C-terminal M75 peptidase domain. This is the first report on structure of a typical EfeO with two domains, postulating a novel metal-binding motif “ExxE-//-D-//-E” in the EfeO C-terminal M75 peptidase domain.