Molecular Basis for Immunity Protein Recognition of a Type VII Secretion System Exported Antibacterial Toxin.
Molecular Basis for Immunity Protein Recognition of a Type VII Secretion System Exported Antibacterial Toxin.
复制标题
免疫蛋白识别VII分泌系统的分子基础导出了抗菌毒素。
DOI：
10.1016/j.jmb.2018.08.027
复制
发表时间：
2018-10-19
影响因子：
5.6
通讯作者：
Whitney JC
中科院分区：
文献类型：
--
作者：
Klein TA;Pazos M;Surette MG;Vollmer W;Whitney JC
革兰氏阳性菌利用 VII 型分泌系统 (T7SS) 促进真核细胞和原核细胞之间的相互作用。在最近的工作中，我们鉴定出中间链球菌中的 TelC 蛋白是 T7SS 输出的脂质 II 磷酸酶，可介导细菌间竞争。 TelC对革兰氏阳性菌的内壁区发挥毒性；然而，姐妹细胞不会发生细胞间中毒，因为它们表达TipC免疫蛋白。在本研究中，我们试图表征 TipC 自我保护的分子基础。通过亚细胞定位和蛋白酶保护分析，我们发现 TipC 是一种膜蛋白，具有 N 端跨膜片段和突出到内壁区域的 C 端 TelC 抑制结构域。非保护性 TipC 旁系同源物的 1.9-Å X 射线晶体结构表明，TipC 蛋白的可溶性结构域采用新月形折叠，由三个 α 螺旋和七链 β 折叠组成。随后的同源引导诱变表明，预测的 TipC β-折叠形成的凹面是其与 TelC 相互作用及其 TelC 抑制活性所必需的。缺乏tipC基因的S. intermedius细胞容易受到细胞间传递的TelC的生长抑制作用；然而，我们发现该菌株的生长不受内源性或过度表达的 TelC 的影响，尽管毒素在培养物上清液中积累。总之，这些数据表明，TipC 的 TelC 抑制活性仅是细胞间转移 TelC 所必需的，并且 T7SS 装置将 TelC 一步转运穿过细胞包膜，绕过其在途中发挥毒性的细胞区室。抗菌 TelC 毒素在内壁区域被膜锚定的 TipC 免疫蛋白中和。 TipC 是一种新月形蛋白质，通过其凹面与 TelC 相互作用。 TelC 和 TipC 在 TelC 产生细胞中被质膜物理分离。 VII 型分泌系统阻止 TelC 进入产生 TelC 的细菌的内壁区域。
Gram-positive bacteria deploy the type VII secretion system (T7SS) to facilitate interactions between eukaryotic and prokaryotic cells. In recent work, we identified the TelC protein from Streptococcus intermedius as a T7SS-exported lipid II phosphatase that mediates interbacterial competition. TelC exerts toxicity in the inner wall zone of Gram-positive bacteria; however, intercellular intoxication of sister cells does not occur because they express the TipC immunity protein. In the present study, we sought to characterize the molecular basis of self-protection by TipC. Using sub-cellular localization and protease protection assays, we show that TipC is a membrane protein with an N-terminal transmembrane segment and a C-terminal TelC-inhibitory domain that protrudes into the inner wall zone. The 1.9-Å X-ray crystal structure of a non-protective TipC paralogue reveals that the soluble domain of TipC proteins adopts a crescent-shaped fold that is composed of three α-helices and a seven-stranded β-sheet. Subsequent homology-guided mutagenesis demonstrates that a concave surface formed by the predicted β-sheet of TipC is required for both its interaction with TelC and its TelC-inhibitory activity. S. intermedius cells lacking the tipC gene are susceptible to growth inhibition by TelC delivered between cells; however, we find that the growth of this strain is unaffected by endogenous or overexpressed TelC, although the toxin accumulates in culture supernatants. Together, these data indicate that the TelC-inhibitory activity of TipC is only required for intercellularly transferred TelC and that the T7SS apparatus transports TelC across the cell envelope in a single step, bypassing the cellular compartment in which it exerts toxicity en route. Antibacterial TelC toxin is neutralized in the inner wall zone by membrane-anchored TipC immunity protein. TipC is a crescent-shaped protein that interacts with TelC via its concave surface. TelC and TipC are physically separated by the plasma membrane in TelC-producing cells. The type VII secretion system prevents TelC access to the inner wall zone in TelC-producing bacteria.
登录
查看更多内容
影响因子：
3.2
作者：
Gerard, Fabien;Brooks, Mark A.;Mengin-Lecreulx, Dominique
通讯作者：
Mengin-Lecreulx, Dominique
影响因子：
3.6
作者：
Crump KE;Bainbridge B;Brusko S;Turner LS;Ge X;Stone V;Xu P;Kitten T
通讯作者：
Kitten T
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
影响因子：
6.7
作者：
Li M;Le Trong I;Carl MA;Larson ET;Chou S;De Leon JA;Dove SL;Stenkamp RE;Mougous JD
通讯作者：
Mougous JD
影响因子：
5.7
作者：
Beck, Christina M.;Morse, Robert P.;Cunningham, David A.;Iniguez, Angelina;Low, David A.;Goulding, Celia W.;Hayes, Christopher S.
通讯作者：
Hayes, Christopher S.