A novel Kunitz-type neurotoxin peptide that inhibited voltage-gated sodium channel was purified and characterized from the skin secretions of rufous-spotted torrent frog, Amolops loloensis. It has a 240-bp cDNA encoding an 79-amino acid residue (aa) precursor protein containing 6 half-cysteines. The precursor was proven to release a 57-aa mature peptide with amino acid sequence, DRNPICNLPPKEGFCLWMMRRSFFNPSKGRCDTFGYRGCGGNKNNFETPRACKEACG. The mature was named amotoxin. Amotoxin shares sequence homology with other Kunitz-type toxins and also has three cysteine bridges. Amotoxin showed an inhibitory ability against trypsin with an inhibitory constant (Ki) of 0.087 μM. To the best of our knowledge, this is the first gene-encoded neurotoxin found in Amolops loloensis. Recombinant amotoxin showed similar functional properties as the native amotoxin. The functional properties of amotoxin may provide insights into the ecological adaptation of amphibians and deepen our understanding about the biological function spectrum of amphibian skin peptides.

纯化了一种新型的抑制电压门控性钠离子通道的Kunitz型神经毒素肽，并从红褐色斑点山蛙Amolops loloensis的皮肤分泌物中进行了表征。它具有一个240 bp的cDNA，编码包含6个半胱氨酸的79个氨基酸残基（aa）前体蛋白。已证明该前体释放出具有氨基酸序列DRNPICNLPPKEGFCLWMMRRSFFNPSKGRCDTFGYRGCGGNKNNFETPRACKEACG的57-aa成熟肽。成熟的被称为阿托莫辛。Amotoxin与其他Kunitz型毒素具有序列同源性，并且还具有三个半胱氨酸桥。Amotoxin对胰蛋白酶具有抑制能力，抑制常数（Ki）为0.087μM。据我们所知，这是在Aloopolos loloensis中发现的第一个基因编码的神经毒素。。重组amotoxin显示出与天然amotoxin类似的功能特性。Amotoxin的功能特性可为两栖动物的生态适应提供见识，并加深我们对两栖动物皮肤肽的生物学功能谱的了解。