Wu Po-Long, Lin Chien-Chu, Lin Ting-Hui, Lee Min-Shi, Wu Wen-Guey
Department of Life Sciences and Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 30013, Taiwan; Refining & Manufacturing Research Institute, CPC Corporation, Chia-Yi 60051, Taiwan.
Department of Life Sciences and Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 30013, Taiwan.
Toxicon. 2016 Aug;118:1-12. doi: 10.1016/j.toxicon.2016.04.034. Epub 2016 Apr 16.
We have previously identified two new P-III type ADAM-like snake venom metalloproteinases (SVMPs), i.e., atragin and kaouthiagin-like, from Taiwan cobra venom and determined their 3D structures with a distinct C- and I-shaped metalloproteinase/disintegrin-like/cysteine-rich (MDC) modular architecture. Herein, we investigated their functional targets to elucidate the role of cobra SVMPs in perturbing wound healing in snakebite victims. We showed that the non-RGD (Arg-Gly-Asp) C-shaped SVMP atragin binds about ten-fold stronger than the RGD-containing I-shaped SVMP kaouthiagin-like to αvβ3 integrin in the surface-immobilized form. Atragin binds to αvβ3 integrin through a novel interaction mode involving distal M and C domains via the RRN sequence motif in the hyper variable loop. In a cell adhesion assay, the adhesion of fibroblasts to atragin was mediated by αvβ3 integrin. Furthermore, atragin inhibited wound healing and suppressed cell migration in a αvβ3 integrin-dependent manner. These results, together with our previous demonstration of non-cytotoxic cobra CTX A5 in targeting αvβ3 integrin, suggest that cobra venom consists of several non-RGD toxins with integrin-binding specificity that could perturb wound healing in snakebite victims.
我们之前从台湾眼镜蛇毒液中鉴定出两种新的P-III型类ADAM蛇毒金属蛋白酶(SVMPs),即阿特拉金和类考齐亚金,并确定了它们具有独特的C形和I形金属蛋白酶/解整合素样/富含半胱氨酸(MDC)模块化结构的三维结构。在此,我们研究了它们的功能靶点,以阐明眼镜蛇SVMPs在干扰蛇咬伤受害者伤口愈合中的作用。我们发现,非RGD(精氨酸-甘氨酸-天冬氨酸)C形SVMP阿特拉金以表面固定形式与αvβ3整合素的结合力比含RGD的I形SVMP类考齐亚金强约十倍。阿特拉金通过一种新的相互作用模式与αvβ3整合素结合,该模式涉及通过高变环中的RRN序列基序的远端M和C结构域。在细胞黏附试验中,成纤维细胞与阿特拉金的黏附由αvβ3整合素介导。此外,阿特拉金以αvβ3整合素依赖性方式抑制伤口愈合并抑制细胞迁移。这些结果,连同我们之前关于眼镜蛇CTX A5靶向αvβ3整合素的非细胞毒性的证明,表明眼镜蛇毒液由几种具有整合素结合特异性的非RGD毒素组成,这些毒素可能会干扰蛇咬伤受害者的伤口愈合。