Exploitation of an iron transporter for bacterial protein antibiotic import.
Exploitation of an iron transporter for bacterial protein antibiotic import.
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DOI：
10.1073/pnas.1713741114
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发表时间：
2017-11-07
影响因子：
11.1
通讯作者：
Kleanthous C
中科院分区：
文献类型：
--
作者：
White P;Joshi A;Rassam P;Housden NG;Kaminska R;Goult JD;Redfield C;McCaughey LC;Walker D;Mohammed S;Kleanthous C
外膜（OM）排斥抗生素，如万古霉素，杀死革兰氏阳性细菌，因此是革兰氏阴性细菌耐多药的主要因素。然而，OM很容易被蛋白质细菌素绕过，细菌素是细菌在争夺资源时释放的毒素，用来杀死它们的邻居。60多年前，人们发现了这些蛋白质是如何穿过线粒体传递有毒物质的，这一直是个谜。我们发现了降解DNA的细菌素pyocin S2 （pyoS2）是如何进入铜绿假单胞菌细胞的。PyoS2诱骗铁转运体FpvAI通过一种与内源性配体铁载体铁吡啶非常相似的过程将其转运到OM上。与它们的后代线粒体和质体不同，细菌没有专门的蛋白质输入系统。然而，矛盾的是，蛋白质细菌素的输入，其机制尚不清楚，支持致病细菌和共生细菌之间的竞争。在这里，利用x射线晶体学、等温滴定量热法、共聚焦荧光显微镜和体内光激活的停滞易位中间体的交联，我们展示了机会性病原体铜绿假单胞菌中的铁转运体FpvAI是如何被劫持，使细菌素pyocin S2 （pyoS2）跨外膜（OM）易位的。FpvAI是一种依赖于tonb的转运蛋白（TBDT），它通过内膜蛋白TonB1与质子动力（PMF）偶联，主动进口小铁载体铁吡啶（Fe-Pvd）。结合FpvAI （Kd = 240 pM）的pyoS2 (pyoS2NTD) n端结构域的晶体结构表明，pyocin模拟Fe-Pvd，在受体中引起相同的构象变化。模拟导致荧光标记的pyoS2NTD通过类似于真正的TBDT配体使用的过程被导入表达fpvai的铜绿假单胞菌细胞。PyoS2NTD通过TonB1诱导塞结构域的力不稳定部分展开，该部分通常阻塞FpvAI的中心通道。随后，脓毒蛋白将其自身的tonb1结合表位运送到外周质，然后被拖过这个狭窄的通道。因此，细菌中充满能量的营养转运体也作为初级蛋白质进口系统，在FpvAI的情况下，导致比转运体天然底物大60倍的蛋白质抗生素在OM中转运。
The outer membrane (OM) excludes antibiotics such as vancomycin that kill gram-positive bacteria, and so is a major contributor to multidrug resistance in gram-negative bacteria. Yet, the OM is readily bypassed by protein bacteriocins, which are toxins released by bacteria to kill their neighbors during competition for resources. Discovered over 60 y ago, it has been a mystery how these proteins cross the OM to deliver their toxic payload. We have discovered how the bacteriocin pyocin S2 (pyoS2), which degrades DNA, enters Pseudomonas aeruginosa cells. PyoS2 tricks the iron transporter FpvAI into transporting it across the OM by a process that is remarkably similar to that used by its endogenous ligand, the siderophore ferripyoverdine. Unlike their descendants, mitochondria and plastids, bacteria do not have dedicated protein import systems. However, paradoxically, import of protein bacteriocins, the mechanisms of which are poorly understood, underpins competition among pathogenic and commensal bacteria alike. Here, using X-ray crystallography, isothermal titration calorimetry, confocal fluorescence microscopy, and in vivo photoactivatable cross-linking of stalled translocation intermediates, we demonstrate how the iron transporter FpvAI in the opportunistic pathogen Pseudomonas aeruginosa is hijacked to translocate the bacteriocin pyocin S2 (pyoS2) across the outer membrane (OM). FpvAI is a TonB-dependent transporter (TBDT) that actively imports the small siderophore ferripyoverdine (Fe-Pvd) by coupling to the proton motive force (PMF) via the inner membrane (IM) protein TonB1. The crystal structure of the N-terminal domain of pyoS2 (pyoS2NTD) bound to FpvAI (Kd = 240 pM) reveals that the pyocin mimics Fe-Pvd, inducing the same conformational changes in the receptor. Mimicry leads to fluorescently labeled pyoS2NTD being imported into FpvAI-expressing P. aeruginosa cells by a process analogous to that used by bona fide TBDT ligands. PyoS2NTD induces unfolding by TonB1 of a force-labile portion of the plug domain that normally occludes the central channel of FpvAI. The pyocin is then dragged through this narrow channel following delivery of its own TonB1-binding epitope to the periplasm. Hence, energized nutrient transporters in bacteria also serve as rudimentary protein import systems, which, in the case of FpvAI, results in a protein antibiotic 60-fold bigger than the transporter’s natural substrate being translocated across the OM.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
3.4
作者：
Elfarash, Ameer;Wei, Qing;Cornelis, Pierre
通讯作者：
Cornelis, Pierre
DOI：
10.1073/pnas.0404549101
发表时间：
2004-11-16
影响因子：
11.1
作者：
Dietz, H;Rief, M
通讯作者：
Rief, M
影响因子：
3.6
作者：
Devanathan, Surendranathan;Postle, Kathleen
通讯作者：
Postle, Kathleen
DOI：
10.1107/s0907444909052925
发表时间：
2010-02
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Adams PD;Afonine PV;Bunkóczi G;Chen VB;Davis IW;Echols N;Headd JJ;Hung LW;Kapral GJ;Grosse-Kunstleve RW;McCoy AJ;Moriarty NW;Oeffner R;Read RJ;Richardson DC;Richardson JS;Terwilliger TC;Zwart PH
通讯作者：
Zwart PH