Caught in the Act: Anthrax Toxin Translocation Complex Reveals insight into the Lethal Factor Unfolding and Refolding mechanism
Caught in the Act: Anthrax Toxin Translocation Complex Reveals insight into the Lethal Factor Unfolding and Refolding mechanism
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陷入困境：炭疽毒素易位复合物揭示了致命因子的展开和重折叠机制
DOI：
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
B. Freudenthal
中科院分区：
文献类型：
--
作者：
Alexandra J Machen;M. Fisher;B. Freudenthal
易位对炭疽毒素的机制至关重要。保护性抗原，这种AB毒素的易位成分，形成一个具有三个关键钳位的寡聚孔，帮助毒素的酶成分致命因子或水肿因子有效进入细胞。LF和EF通过保护性抗原孔转运，内核体和细胞质之间的pH梯度是驱动力。易位过程的结构细节尽管具有重要的生物学意义，但仍然难以捉摸。为了克服研究易位中间体的技术挑战，我们开发了一种新的方法来固定，转化和稳定炭疽毒素。在这里，我们报道了一个低温电镜快照的PApore转移的n端结构域的LF。当LFN在α钳附近展开，通过Φ钳移位，并开始在电荷钳中重新折叠时，所得到的3.1和3.2 A结构的复合物追踪LFN。此外，β管通道内的螺旋密度表明LF二级结构元件在电荷钳位开始重新折叠。我们得出结论，炭疽毒素使用延长的β桶在通道出口之前有效地折叠酶有效载荷。这种重折叠机制对其他蛋白质转运毒素的孔长也有更广泛的意义。
ABSTRACT Translocation is essential to the anthrax toxin mechanism. Protective antigen, the translocon component of this AB toxin, forms an oligomeric pore with three key clamp sites that aid in the efficient entry of lethal factor or edema factor, the enzymatic components of the toxin, into the cell. LF and EF translocate through the protective antigen pore with the pH gradient between the endosome and the cytosol acting as the driving force. Structural details of the translocation process have remained elusive despite their biological importance. To overcome the technical challenges of studying translocation intermediates, we developed a novel method to immobilize, transition, and stabilize anthrax toxin. Here, we report a cryoEM snapshot of PApore translocating the N-terminal domain of LF. The resulting 3.1 and 3.2 A structures of the complex trace LFN as it unfolds near the α clamp, translocates through the Φ clamp, and begins to refold in the charge clamp. In addition, helical density inside the β barrel channel suggests LF secondary structural elements begin to refold at the charge clamp site. We conclude the anthrax toxin uses an extended β barrel to efficiently fold the enzymatic payload prior to channel exit. This refolding mechanism has broader implications for pore length of other protein translocating toxins.
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影响因子：
2.9
作者：
Miller, CJ;Elliott, JL;Collier, RJ
通讯作者：
Collier, RJ
影响因子：
16
作者：
Zhang, Fan;Hu, Min;Tian, Geng;Zhang, Ping;Finley, Daniel;Jeffrey, Philip D.;Shi, Yigong
通讯作者：
Shi, Yigong
影响因子：
3
作者：
Mastronarde, DN
通讯作者：
Mastronarde, DN
影响因子：
--
作者：
Ritchie, T. K.;Grinkova, Y. V.;Bayburt, T. H.;Denisov, I. G.;Zolnerciks, J. K.;Atkins, W. M.;Sligar, S. G.
通讯作者：
Sligar, S. G.
影响因子：
15
作者：
Denisov, IG;Grinkova, YV;Sligar, SG
通讯作者：
Sligar, SG