Conformational switching, refolding and membrane insertion of the diphtheria toxin translocation domain.
Conformational switching, refolding and membrane insertion of the diphtheria toxin translocation domain.
复制标题
DOI：
10.1016/bs.mie.2020.12.016
复制
发表时间：
2021
影响因子：
--
通讯作者：
Vasquez-Montes V
中科院分区：
文献类型：
--
作者：
Ladokhin AS;Kyrychenko A;Rodnin MV;Vasquez-Montes V
白喉毒素是利用细胞进入内体途径的许多细菌毒素之一，这是通过毒素的易位(T)结构域桥接内体膜来确保的。内体酸化触发t结构域的一系列构象变化，首先发生在水环境中，随后发生在膜环境中。这些重排最终导致建立膜插入构象和毒素的催化部分易位到细胞质中。我们在这里讨论了将位点选择性标记与各种光谱方法相结合的策略，以表征质子依赖的构象开关和白喉毒素t结构域的膜插入的结构和热力学方面。讨论的方法包括FRET， FCS和深度依赖荧光猝灭与脂质附着的溴原子和自旋探针。t结构域的膜插入途径包含多个中间体，并受组氨酸和酸性残基质子化的交错ph依赖转变控制。目前的数据表明，脂质双分子层在t结构域的功能中起着积极的作用，所谓的开放通道状态并不构成易位途径，而可能是易位的副产品。这里提出的光谱方法广泛适用于许多其他生理和生物医学感兴趣的系统，其中构象变化可导致膜插入（例如，其他细菌毒素，宿主防御肽，肿瘤靶向phillip肽和凋亡调节因子Bcl-2家族成员）。
Diphtheria toxin is among many bacterial toxins that utilize the endosomal pathway of cellular entry, which is ensured by the bridging of the endosomal membrane by the toxin’s translocation (T) domain. Endosomal acidification triggers a series of conformational changes of the T-domain, that take place first in aqueous and subsequently in membranous milieu. These rearrangements ultimately result in establishing membrane-inserted conformation(s) and translocation of the catalytic moiety of the toxin into the cytoplasm. We discuss here the strategy for combining site-selective labeling with various spectroscopic methods to characterize structural and thermodynamic aspects of protonation-dependent conformational switching and membrane insertion of the diphtheria toxin T-domain. Among the discussed methods are FRET, FCS and depth-dependent fluorescence quenching with lipid-attached bromine atoms and spin probes. The membrane-insertion pathway of the T-domain contains multiple intermediates and is governed by staggered pH-dependent transitions involving protonation of histidines and acidic residues. Presented data demonstrate that the lipid bilayer plays an active part in T-domain functioning and that the so-called Open-Channel State does not constitute the translocation pathway, but is likely to be a byproduct of the translocation. The spectroscopic approaches presented here are broadly applicable to many other systems of physiological and biomedical interest for which conformational changes can lead to membrane insertion (e.g., other bacterial toxins, host defense peptides, tumor-targeting pHLIP peptides and members of Bcl-2 family of apoptotic regulators).
登录
查看更多内容
影响因子：
4.2
作者：
Ghatak C;Rodnin MV;Vargas-Uribe M;McCluskey AJ;Flores-Canales JC;Kurnikova M;Ladokhin AS
通讯作者：
Ladokhin AS
影响因子：
2.4
作者：
Kyrychenko, Alexander;Rodnin, Mykola V.;Ladokhin, Alexey S.
通讯作者：
Ladokhin, Alexey S.
DOI：
10.1073/pnas.94.8.3668
发表时间：
1997-04-15
影响因子：
11.1
作者：
Hsu, YT;Wolter, KG;Youle, RJ
通讯作者：
Youle, RJ
影响因子：
3.8
作者：
Huynh, P D;Cui, C;Zhan, H;Oh, K J;Collier, R J;Finkelstein, A
通讯作者：
Finkelstein, A
影响因子：
5.6
作者：
Kyrychenko, Alexander;Rodnin, Mykola V.;Posokhov, Yevgen O.;Holt, Andrea;Pucci, Bernard;Killian, J. Antoinette;Ladokhin, Alexey S.
通讯作者：
Ladokhin, Alexey S.