Functional analysis of an alpha-helical antimicrobial peptide derived from a novel mouse defensin-like gene.
Functional analysis of an alpha-helical antimicrobial peptide derived from a novel mouse defensin-like gene.
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DOI：
10.1016/j.bbrc.2010.07.028
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发表时间：
2010-08
影响因子：
3.1
通讯作者：
A. Kawaguchi;Tadaki Suzuki;Takashi Kimura;N. Sakai;T. Ayabe;H. Sawa;H. Hasegawa
中科院分区：
文献类型：
--
作者：
A. Kawaguchi;Tadaki Suzuki;Takashi Kimura;N. Sakai;T. Ayabe;H. Sawa;H. Hasegawa
基因编码的抗菌肽 (AMP) 是许多物种先天免疫系统的重要组成部分。使用对位于 β-防御素翻译区之外的保守序列具有特异性的引物对小鼠组织中的 β-防御素基因表达进行分析，鉴定出一个新的小基因。该新基因具有114bp的开放阅读框，编码37个氨基酸残基的预测蛋白。基因组数据库检索显示，该新基因的基因位点和外显子1序列与亚组1小鼠β-防御素相似。合成了源自该新基因的氨基酸序列的小肽 K17 (FSPQMLQDIIEKKTKIL)。化学合成肽的圆二色性(CD)光谱分析表明，该肽在水溶液中呈现无规卷曲构象，但在三氟乙醇或十二烷基硫酸钠存在的模拟膜环境下，该肽呈现螺旋构象。该肽对鼠伤寒沙门氏菌（革兰氏阴性）和金黄色葡萄球菌（革兰氏阳性）具有杀菌活性；它在哺乳动物细胞培养物中不具有细胞毒性，在红细胞培养物中不具有溶血性。这些结果表明 K17 可能是治疗细菌感染的候选疗法。
Gene-encoded antimicrobial peptides (AMPs) are an essential component of the innate immune system in many species. Analysis of β-defensin gene expression in mouse tissue using primers that were specific for conserved sequences located outside of the β-defensin translated region identified a novel small gene. The novel gene had an open reading frame of 114bp and encoded a predicted protein of 37 amino acid residues. A search of the genome database revealed that the gene locus and the sequence of exon 1 of this novel gene were similar to subgroup 1 mouse β-defensins. A small peptide, K17 (FSPQMLQDIIEKKTKIL), derived from the amino acid sequence of this novel gene was synthesized. Circular dichroism (CD) spectroscopic analysis of chemically synthesized peptide demonstrated that the peptide exhibited random coil conformation in aqueous solution, but the peptide adopted helical conformation in the presence of trifluoroethanol or sodium dodecyl sulfate, a membrane-mimicking environment. The peptide exhibited bactericidal activity against Salmonella enterica serovar Typhimurium (Gram negative) and Staphylococcus aureus (Gram positive); it was not cytotoxic in cultures of mammalian cells or hemolytic in cultures of erythrocytes. These results suggested that K17 may be a candidate therapeutic for the treatment of bacterial infection.