Structural Insights into Recognition of Triple-helical β-Glucans by an Insect Fungal Receptor
Structural Insights into Recognition of Triple-helical β-Glucans by an Insect Fungal Receptor
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DOI：
10.1074/jbc.m111.256701
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发表时间：
2011-08-19
影响因子：
4.8
通讯作者：
Yamaguchi, Yoshiki
中科院分区：
文献类型：
--
作者：
Kanagawa, Mayumi;Satoh, Tadashi;Yamaguchi, Yoshiki
检测病原体的先天能力是通过模式识别受体实现的，模式识别受体识别非自身成分，如- 1,3-葡聚糖。1,3-葡聚糖形成由链间氢键稳定的三螺旋结构。β 1,3-葡聚糖识别蛋白(β GRP)/革兰氏阴性细菌结合蛋白3 （GNBP3）是一种模式识别受体，与长结构的β 1,3-葡聚糖结合，启动先天免疫反应。然而，结合细节和特异性如何在这些受体中实现仍然是重要的未解决的问题。我们解决了β - GRP/GNBP3的n端β 1,3-葡聚糖识别域（β GRP- n）与β 1,3-连接葡萄糖六聚体层状己糖配合物的晶体结构。在晶体中，三个结构层状己糖酶同时通过六个葡萄糖残基（每条链两个）与一个β GRP-N相互作用。与β GRP-N结合的层状己糖酶的空间排列几乎与β 1,3-葡聚糖三螺旋结构相同。因此，我们的晶体结构和定点诱变数据为这些受体对- 1,3-葡聚糖的三螺旋结构的独特识别提供了结构基础。
The innate ability to detect pathogens is achieved by pattern recognition receptors, which recognize non-self-components such as beta 1,3-glucan. beta 1,3-Glucans form a triple-helical structure stabilized by interchain hydrogen bonds. beta 1,3-Glucan recognition protein (beta GRP)/Gram-negative bacteria-binding protein 3 (GNBP3), one of the pattern recognition receptors, binds to long, structured beta 1,3-glucan to initiate innate immune response. However, binding details and how specificity is achieved in such receptors remain important unresolved issues. We solved the crystal structures of the N-terminal beta 1,3-glucan recognition domain of beta GRP/GNBP3 (beta GRP-N) in complex with the beta 1,3-linked glucose hexamer, laminarihexaose. In the crystals, three structured laminarihexaoses simultaneously interact through six glucose residues (two from each chain) with one beta GRP-N. The spatial arrangement of the laminarihexaoses bound to beta GRP-N is almost identical to that of a beta 1,3-glucan triple-helical structure. Therefore, our crystallographic structures together with site-directed mutagenesis data provide a structural basis for the unique recognition by such receptors of the triple-helical structure of beta 1,3-glucan.