World Class University Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea 151-742.
Poult Sci. 2014 Apr;93(4):864-70. doi: 10.3382/ps.2013-03670.
The antimicrobial peptides (AMP) are important elements of the first line of defense against pathogens in animals, and an important constituent of innate immunity. Antimicrobial peptides act on a broad spectrum of microbial organisms. NK-Lysin is a cationic antibacterial peptide that was originally isolated from porcine intestinal tissue based on its antibacterial activity. We synthesized peptides corresponding to each helical region of chicken NK-lysin and analyzed their secondary structures in addition to their antimicrobial activity. Circular dichroism spectroscopy of the synthetic chicken NK-lysin (cNK-78) and 4 small peptides in negatively charged liposomes demonstrated transition in the conformation of α-helical peptides relative to the charged environment. Chicken NK-lysin inhibits the growth of a representative gram-negative bacterium, Escherichia coli. The antimicrobial activity of 2 peptides designated H23 and H34 was similar to that of mature NK-lysin, cNK-78. Microscopic analyses revealed the death of bacterium with disrupted membranes after peptide treatment, suggesting that chicken NK-lysin, an alpha-helical cationic peptide, exerts its antimicrobial activity by damaging the bacterial cell membrane.
抗菌肽 (AMP) 是动物抵御病原体的第一道防线的重要组成部分，也是先天免疫的重要组成部分。抗菌肽对广泛的微生物具有作用。NK-溶菌素是一种阳离子抗菌肽，最初是根据其抗菌活性从猪肠组织中分离出来的。我们合成了对应于鸡 NK-溶菌素 (cNK-78) 每个螺旋区的肽，并分析了它们的二级结构及其抗菌活性。合成的鸡 NK-溶菌素 (cNK-78) 和带负电荷的脂质体中的 4 个小肽的圆二色性光谱表明，相对于带电环境，α-螺旋肽的构象发生了转变。鸡 NK-溶菌素抑制了代表性革兰氏阴性菌大肠杆菌的生长。指定为 H23 和 H34 的 2 个肽的抗菌活性与成熟 NK-溶菌素 cNK-78 相似。显微镜分析显示，肽处理后细胞膜破裂的细菌死亡，表明α-螺旋阳离子肽鸡 NK-溶菌素通过破坏细菌细胞膜发挥其抗菌活性。
