Life Sciences College of Nanjing Agricultural University, Nanjing 210095, Jiangsu, China.
Gene. 2013 Feb 10;514(2):99-104. doi: 10.1016/j.gene.2012.11.007. Epub 2012 Nov 28.
A 255-bp cDNA encoding an 84-amino acid residue (aa) precursor protein containing 8 half-cysteines was cloned from the skin of the frog, Ceratophrys calcarata. By sequence comparison and signal peptide prediction, the precursor was predicted to release a 63-aa mature peptide with amino acid sequence, NVTPATKPTPSKPGYCRVMDELILCPDPPLSKDLCKNDSDCPGAQKCCYRTCIMQCLPPIFRE. The mature was named ceratoxin. Ceratoxin shares significant sequence similarity with the toxin family of waprins containing the whey acidic protein-type (WAP) four-disulfide core domain found in snake venoms. Antimicrobial and trypsin-inhibitory abilities of recombinant ceratoxin were tested. Recombinant ceratoxin showed strong antimicrobial activities against wide spectrum of microorganisms including Gram-negative and Gram-positive bacteria and fungi. It had no serine protease-inhibitory activity. The current results suggested that the snake venom-like waprin with antimicrobial activities in the frog skin plays a role in innate immunity.
从蛙科动物棘胸蛙的皮肤中克隆出一段编码 255 个碱基对的 cDNA，该 cDNA 编码一个含有 8 个半胱氨酸的 84 个氨基酸残基的前体蛋白。通过序列比较和信号肽预测，该前体蛋白预测释放一个含有氨基酸序列 NVTPATKPTPSKPGYCRVMDELILCPDPPLSKDLCKNDSDCPGAQKCCYRTCIMQCLPPIFRE 的 63 个氨基酸成熟肽。成熟肽被命名为棘蛙毒素。棘蛙毒素与包含蛇毒中乳白蛋白酸性蛋白型（WAP）四硫键核心结构域的毒素家族具有显著的序列相似性。对重组棘蛙毒素的抗菌和胰蛋白酶抑制活性进行了测试。重组棘蛙毒素对包括革兰氏阴性和革兰氏阳性细菌以及真菌在内的广谱微生物具有很强的抗菌活性。它没有丝氨酸蛋白酶抑制活性。目前的结果表明，具有抗菌活性的蛇毒样 Waprin 在蛙皮中发挥先天免疫作用。
