Receptor variability-driven evolution of snake toxins  

作　　者：Xian-Hong Ji Shang-Fei Zhang Bin Gao Shun-Yi Zhu 

机构地区：[1]Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology,Chinese Academy of Sciences, Beijing 100101, China [2]University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Zoological Research》2018年第6期431-436,共6页动物学研究（英文）

基　　金：supported by the National Natural Science Foundation of China(Grant No.31570773);State Key Laboratory of Integrated Management of Pest Insects and Rodents(Chinese IPM1707)

摘　　要：Three-finger toxins （TFTs） are well-recognized non- enzymatic venom proteins found in snakes. However, although TFTs exhibit accelerated evolution, the drivers of this evolution remain poorly understood. The structural complexes between long-chain α-neurotoxins, a subfamily of TFTs, and their nicotinic acetylcholine receptor targets have been determined in previous research, providing an opportunity to address such questions. In the current study, we observed several previously identified positively selected sites （PSSs） and the highly variable C-terminal loop of these toxins at the toxin/receptor interface. Of interest, analysis of the molecular adaptation of the toxin-recognition regions in the corresponding receptors provided no statistical evidence for positive selection. However, these regions accumulated abundant amino acid variations in the receptors from the prey of snakes, suggesting that accelerated substitution of TFTs could be a consequence of adaptation to these variations. To the best of our knowledge, this atypical evolution, initially discovered in scorpions, is reported in snake toxins for the first time and may be applicable for the evolution of toxins from other venomous animals.Three-finger toxins （TFTs） are well-recognized non- enzymatic venom proteins found in snakes. However, although TFTs exhibit accelerated evolution, the drivers of this evolution remain poorly understood. The structural complexes between long-chain α-neurotoxins, a subfamily of TFTs, and their nicotinic acetylcholine receptor targets have been determined in previous research, providing an opportunity to address such questions. In the current study, we observed several previously identified positively selected sites （PSSs） and the highly variable C-terminal loop of these toxins at the toxin/receptor interface. Of interest, analysis of the molecular adaptation of the toxin-recognition regions in the corresponding receptors provided no statistical evidence for positive selection. However, these regions accumulated abundant amino acid variations in the receptors from the prey of snakes, suggesting that accelerated substitution of TFTs could be a consequence of adaptation to these variations. To the best of our knowledge, this atypical evolution, initially discovered in scorpions, is reported in snake toxins for the first time and may be applicable for the evolution of toxins from other venomous animals.

关 键 词：Three-finger toxins Nicotinic acetylcholine receptor DRIVER 

分 类 号：Q951.3[生物学—动物学]