Identification and polymorphism discovery of the cathelicidins, Lf‐CATHs in ranid amphibian (Limnonectes fragilis)
Identification and polymorphism discovery of the cathelicidins, Lf‐CATHs in ranid amphibian (Limnonectes fragilis)
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DOI：
10.1111/febs.12521
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发表时间：
2013-12
期刊：
影响因子：
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通讯作者：
Haining Yu;Shasha Cai;Jiuxiang Gao;Songyan Zhang;Yiling Lu;Xue Qiao;Hailong Yang;Yipeng Wang
中科院分区：
文献类型：
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作者：
Haining Yu;Shasha Cai;Jiuxiang Gao;Songyan Zhang;Yiling Lu;Xue Qiao;Hailong Yang;Yipeng Wang
为了保护自己免受微生物的入侵，两栖动物，特别是蛙，可能配备了复杂的抗菌肽（AMP）组合。两栖类动物皮肤分泌的AMP和cathelicidins可能共同构成宿主的天然免疫系统。Cathelicidins是一组在白细胞和上皮细胞中发现的阳离子肽，并且它们在几乎所有哺乳动物物种中发现的早期先天免疫防御中发挥核心作用。然而，它们很少被报道来自两栖动物。在这里，我们报告的鉴定和发现多态性cathelicidins在淡水脆弱。表达谱表明，在青蛙的脾、肝和肾中有高水平的凯萨林菌素转录本，而在肺、皮肤和胃中有较低的水平。根据两栖动物独特的蛋白水解模式，预测前原肽的R125和L121分别是蛋白酶产生成熟肽Lf-CATH 1和Lf-CATH 2的加工位置。两者均由30个氨基酸残基组成，其中两个半胱氨酸在一些已知的两栖动物cathelicidins中位置保守。同源性建模分析显示，Lf‐ CATH 1和Lf ‐2采用主要为α螺旋的三级结构，这是小阳离子凯萨林菌素家族肽的代表。重组Lf‐ CATH 1（rLf‐ CATH 1）在大肠杆菌中生产。合成Lf‐ CATH 1和2在体外对广谱微生物（包括标准和临床分离的耐药菌株）显示出强效抗菌活性，同时显示出可忽略的溶血和细胞毒性。
To protect themselves against the invasion of microorganisms, amphibians, especially the Rana frogs, are possibly equipped with complex combinations of antimicrobial peptides (AMPs). The two major AMP families, ranid skin secretion AMPs and cathelicidins might together constitute the host innate immune system of amphibians. Cathelicidins are a group of cationic peptides found in leukocytes and epithelial cells, and they play a central role in the early innate immune defense found in virtually all species of mammals. However, they have rarely been reported from amphibians. Here, we report the identification and discovery of polymorphism cathelicidins in Limnonectes fragilis. The expression profile indicated high cathelicidin transcript levels in frog spleen, liver and kidney, but lower levels in lung, skin and stomach. According to the amphibian's unique proteolytic pattern, R125 and L121 of the prepropeptides are predicted to be the processing positions for protease to generate the mature peptides, Lf‐CATH1 and ‐2, respectively. Both consist of 30 amino acid residues, of which two were cysteines positionally conserved among a few known amphibian cathelicidins. Homology modeling analysis revealed that Lf‐CATH1 and ‐2 adopt a tertiary structure with a mostly α helix that is representative of small cationic cathelicidin family peptides. Recombinant Lf‐CATH1 (rLf‐CATH1) was produced in Escherichia coli. Synthetic Lf‐CATH1 and ‐2 displayed potent antimicrobial activities in vitro against a broad spectrum of microorganisms, including standard and clinically isolated drug‐resistant strains, while showing neglectable hemolysis and cytotoxicities.