Wu Yuxin, Long Qilin, Xu Ying, Guo Shaodong, Chen Tianbao, Wang Lei, Zhou Mei, Zhang Yingqi, Shaw Chris, Walker Brian
Natural Drug Discovery Group, School of Pharmacy, Queen's University Belfast, Belfast BT12 6BA, Northern Ireland, U.K.
Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, 123A Cater Mattil Hall, 2253 TAMU, College Station, TX 77843, U.S.A.
Biosci Rep. 2017 Apr 28;37(2). doi: 10.1042/BSR20160593. Print 2017 Apr 30.
Frog skin secretions contain complex peptidomes and peptidic protease inhibitors that are one of the biologically and structurally described groups of components. In the present study, by use of molecular 'shotgun' cloning and LC MS/MS fractionation sequencing, a novel Bowman-Birk-type heptadecapeptide (AALKGCWTKSIPPKPCF-amide), named rypsin nhibitor (OSTI), with a canonical Cys-Cys disulfide bridge, was isolated and identified in piebald odorous frog () skin secretion. A synthetic replicate of OSTI-exhibited trypsin inhibitory activity with a value of 0.3 ± 0.04 nM and also a tryptase inhibitory effect with a of 2.5 ± 0.6 μM. This is the first time that this property has been reported for a peptide originating from amphibian sources. In addition, substituting lysine (K) with phenylalanine (F) at the presumed P1 position, completely abrogated the trypsin and tryptase inhibition, but produced a strong chymotrypsin inhibition with a of 1.0 ± 0.1 μM. Thus, the specificity of this peptidic protease inhibitor could be optimized through modifying the amino acid residue at the presumed P1 position and this novel native OSTI, along with its analogue, [Phe]-OSTI, have expanded the potential drug discovery and development pipeline directed towards alleviation of serine protease-mediated pathologies.
蛙皮分泌物含有复杂的肽组和肽类蛋白酶抑制剂，它们是已从生物学和结构上进行描述的成分组之一。在本研究中，通过分子“鸟枪法”克隆和液相色谱-串联质谱（LC MS/MS）分级测序，在花斑臭蛙（）的皮肤分泌物中分离并鉴定出一种新型的鲍曼-伯克型十七肽（AALKGCWTKSIPPKPCF-酰胺），命名为胰蛋白酶抑制剂（OSTI），其具有典型的半胱氨酸-半胱氨酸二硫键。OSTI的合成复制品表现出胰蛋白酶抑制活性，其 值为0.3±0.04 nM，还具有对类胰蛋白酶的抑制作用，其 为2.5±0.6 μM。这是首次报道源自两栖动物的肽具有这种特性。此外，在假定的P1位置用苯丙氨酸（F）替代赖氨酸（K），完全消除了对胰蛋白酶和类胰蛋白酶的抑制作用，但产生了对糜蛋白酶的强烈抑制作用，其 为1.0±0.1 μM。因此，这种肽类蛋白酶抑制剂的特异性可以通过修饰假定的P1位置的氨基酸残基来优化，并且这种新型天然OSTI及其类似物[Phe]-OSTI扩展了针对减轻丝氨酸蛋白酶介导的病理状况的潜在药物发现和开发途径。
