Mapping of a microbial protein domain involved in binding and activation of the TLR2/TLR1 heterodimer.
Mapping of a microbial protein domain involved in binding and activation of the TLR2/TLR1 heterodimer.
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DOI：
10.4049/jimmunol.0803737
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发表时间：
2009-03-01
期刊：
影响因子：
--
通讯作者：
Hajishengallis G
中科院分区：
文献类型：
--
作者：
Liang S;Hosur KB;Lu S;Nawar HF;Weber BR;Tapping RI;Connell TD;Hajishengallis G
LT-IIb-B5是一种产肠毒素大肠杆菌的环状寡聚体蛋白，已知可激活TLR 2/TLR 1异源二聚体（TLR 2/1）。我们研究了LT-IIb-B5与TLR 2/1相互作用的分子基础，以确定LT-IIb-B5的结构-功能关系，此外，还深入了解TLR 2/1如何识别无法装入其脂质结合口袋的大型非酰化蛋白配体，如先前所示的Pam 3CSK 4脂肽。我们首先确定了LT-IIb-B5孔上部区域的四个关键残基：对应点突变体（M69 E，A70 D，L73 E，S74 D）在结合TLR 2或TLR 1方面有缺陷，并且不能激活抗原呈递细胞，尽管保留了完整的神经节苷脂结合能力。在TLR 2/1-Pam 3CSK 4复合物的晶体结构中确定的TLR 2/1二聚体界面中的点突变导致Pam 3CSK 4和LT-IIb-B5的激活减少。对LT-IIb-B5与TLR 2/1的这种明显“主要”活化构象的相互作用的对接分析揭示，LT-IIb-B5可能主要接触TLR 2中心结构域的凸面。虽然TLR 1/LT-IIb-B5界面相对较小，但发现TLR 1中心结构域中富含亮氨酸的重复基序9-12对于LT-IIb-B5协同TLR 2诱导的细胞活化至关重要。此外，推定的LT-IIb-B5结合位点与Pam 3CSK 4的结合位点部分重叠;与此一致，Pam 3CSK 4抑制LT-IIb-B5的TLR 2结合，尽管不像自竞争抑制那样有效。总之，我们确定了LT-IIb-B5的上孔区域作为TLR 2/1相互作用域，其在不同于Pam 3CSK 4的位点处接触异二聚体受体，尽管与Pam 3CSK 4的位点重叠。
LT-IIb-B5, a doughnut-shaped oligomeric protein from enterotoxigenic Escherichia coli, is known to activate the TLR2/TLR1 heterodimer (TLR2/1). We investigated the molecular basis of the LT-IIb-B5 interaction with TLR2/1 in order to define the structure-function relationship of LT-IIb-B5 and, moreover, to gain an insight into how TLR2/1 recognizes large, non-acylated protein ligands that cannot fit within its lipid-binding pockets, as previously shown for the Pam3CSK4 lipopeptide. We first identified four critical residues in the upper region of the LT-IIb-B5 pore: Corresponding point mutants (M69E, A70D, L73E, S74D) were defective in binding TLR2 or TLR1 and could not activate antigen-presenting cells, despite retaining full ganglioside-binding capacity. Point mutations in the TLR2/1 dimer interface, as determined in the crystallographic structure of the TLR2/1-Pam3CSK4 complex, resulted in diminished activation by both Pam3CSK4 and LT-IIb-B5. Docking analysis of the LT-IIb-B5 interaction with this apparently “predominant” activation conformation of TLR2/1 revealed that LT-IIb-B5 may primarily contact the convex surface of the TLR2 central domain. Although the TLR1/LT-IIb-B5 interface is relatively smaller, the leucine-rich repeat motifs 9–12 in the central domain of TLR1 were found to be critical for cooperative TLR2-induced cell activation by LT-IIb-B5. Moreover, the putative LT-IIb-B5 binding site overlaps partially with that of Pam3CSK4; consistent with this, Pam3CSK4 suppressed TLR2 binding of LT-IIb-B5, albeit not as potently as self-competitive inhibition. In conclusion, we identified the upper pore region of LT-IIb-B5 as a TLR2/1 interactive domain, which contacts the heterodimeric receptor at a site that is distinct from, though overlaps with, that of Pam3CSK4.
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影响因子：
64.8
作者：
Chinchilla, Delphine;Zipfel, Cyril;Boller, Thomas
通讯作者：
Boller, Thomas
影响因子：
4.4
作者：
Massari, P;Visintin, A;Wetzler, LM
通讯作者：
Wetzler, LM
影响因子：
30.5
作者：
Latz, Eicke;Verma, Anjali;Golenbock, Douglas T.
通讯作者：
Golenbock, Douglas T.
影响因子：
2.2
作者：
Lutz, MB;Kukutsch, N;Schuler, G
通讯作者：
Schuler, G
DOI：
10.1107/s0907444998003254
发表时间：
1998-09-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
Brunger, AT;Adams, PD;Warren, GL
通讯作者：
Warren, GL