Crystal structure of a cytocidal protein from lamprey and its mechanism of action in the selective killing of cancer cells
Crystal structure of a cytocidal protein from lamprey and its mechanism of action in the selective killing of cancer cells
复制标题
七鳃鳗杀细胞蛋白的晶体结构及其选择性杀伤癌细胞的作用机制
DOI：
10.1186/s12964-019-0358-y
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发表时间：
2019-05-27
影响因子：
8.4
通讯作者：
Li, Qingwei
中科院分区：
文献类型：
--
作者：
Pang, Yue;Gou, Meng;Li, Qingwei
研究背景七鳃鳗免疫蛋白（LIP）对肿瘤细胞具有杀伤活性，但其选择性识别和杀伤肿瘤细胞的机制尚不清楚。方法通过超分辨显微镜、晶体结构分析、聚糖芯片分析、SPR实验、流式细胞仪分析、计算机研究和质谱分析等方法，确定了LIP的作用模式，结果我们测定了LIP的晶体结构，分辨率为2.25 μ m。LIP具有105 μ m × 30 μ m × 30 μ m的细长结构，包含N-末端凝集素模块和C-末端气溶素模块。此外，Phe 209-Gly 232区域被预测插入到脂双层中形成一个跨膜β-桶，其中疏水残基面向脂双层，极性残基构成孔的亲水腔。我们发现LIP能够杀死各种人类癌细胞，对正常细胞的影响最小。值得注意的是，通过耦合生物化学和计算研究，我们提出了一个假设的机制，涉及双重选择性识别和有效的结合依赖于GPI锚定蛋白（GPI-AP）和鞘磷脂（SM）在脂筏上的N-连接聚糖。此外，凝集素模块与GPI-AP上的双触角双唾液酸化非岩藻糖基化N-聚糖或含唾液酸化刘易斯X聚糖结构的特异性结合触发气单胞菌溶素模块的实质性构象变化，其与SM相互作用，最终导致膜的形成-结论LIP作为一种海洋蛋白，在肿瘤的靶向治疗和早期诊断方面具有巨大的应用潜力。人类
BackgroundIn previous research, we found that lamprey immune protein (LIP) possessed cytocidal activity against tumor cells, but the mechanism of the selective recognition and killing of tumor cells by LIP was not identified.MethodsSuperresolution microscopy, crystallographic structural analysis, glycan chip assay, SPR experiments, FACS assays, computational studies and mass spectrometric analysis firmly establish the mode of action of LIP, which involves dual selective recognition and efficient binding.ResultsWe determined the overall crystallographic structure of LIP at a resolution of 2.25 Å. LIP exhibits an elongated structure with dimensions of 105 Å × 30 Å × 30 Å containing an N-terminal lectin module and a C-terminal aerolysin module. Moreover, the Phe209-Gly232region is predicted to insert into the lipid bilayer to form a transmembrane β-barrel, in which the hydrophobic residues face the lipid bilayer, and the polar residues constitute the hydrophilic lumen of the pore. We found that LIP is able to kill various human cancer cells with minimal effects on normal cells. Notably, by coupling biochemical and computational studies, we propose a hypothetical mechanism that involves dual selective recognition and efficient binding dependent on both N-linked glycans on GPI-anchored proteins (GPI-APs) and sphingomyelin (SM) in lipid rafts. Furthermore, specific binding of the lectin module with biantennary bisialylated nonfucosylated N-glycan or sialyl Lewis X-containing glycan structures on GPI-APs triggers substantial conformational changes in the aerolysin module, which interacts with SM, ultimately resulting in the formation of a membrane-bound oligomer in lipid rafts.ConclusionsLIP holds great potential for the application of a marine protein towards targeted cancer therapy and early diagnosis in humans.