Zhong L, Putnam R J, Johnson W C, Rao A G
Department of Traits and Technology Development, Pioneer Hi-Bred International, Inc., Johnston, Iowa, USA.
Int J Pept Protein Res. 1995 Apr;45(4):337-47. doi: 10.1111/j.1399-3011.1995.tb01047.x.
A large proportion of antimicrobial peptides share a common structural feature that is critical to their antimicrobial activity, i.e. amphipathic alpha-helices. The amphipathy of a polypeptide chain can be quantitated through the value of the hydrophobic moment. Generally, antimicrobial peptides are characterized by high hydrophobic moment and low hydrophobicity values. Using these criteria we have identified two short segments that possess hydrophobic moment properties associated with known antimicrobial peptides. Using in vitro assays the segment derived from the protein perforin displays no antifungal or antibacterial activity and, while showing no alpha-helicity in buffer or liposomes, exhibits a modest degree of alpha-helical structure in the presence of the alpha-helical inducer, 2,2,2-trifluoroethanol. However, rational modifications result in a derivative which assumes an alpha-helical conformation in the presence of liposomes, exhibits potent antifungal activity against plant fungal pathogens, has significant antibacterial activity, effects leakage of a fluorescent dye from acidic liposomes and is devoid of hemolytic activity. Results are also presented for a segment derived from the human immunodeficiency virus envelope protein. We suggest that the identification of putative amphipathic structures in proteins may provide a useful starting strategy in the design and synthesis of antimicrobial peptides.
很大一部分抗菌肽具有一种对其抗菌活性至关重要的共同结构特征，即两亲性α-螺旋。多肽链的两亲性可以通过疏水矩的值来定量。一般来说，抗菌肽的特征是具有高疏水矩和低疏水性值。利用这些标准，我们鉴定出了两个短片段，它们具有与已知抗菌肽相关的疏水矩特性。通过体外试验，来源于穿孔素蛋白的片段没有抗真菌或抗菌活性，在缓冲液或脂质体中不显示α-螺旋性，但在α-螺旋诱导剂2,2,2-三氟乙醇存在的情况下呈现出适度的α-螺旋结构。然而，合理的修饰产生了一种衍生物，它在脂质体存在时呈现α-螺旋构象，对植物真菌病原体具有强大的抗真菌活性，具有显著的抗菌活性，能使荧光染料从酸性脂质体中泄漏，并且没有溶血活性。还给出了来源于人类免疫缺陷病毒包膜蛋白的一个片段的结果。我们认为，鉴定蛋白质中假定的两亲性结构可能为抗菌肽的设计和合成提供一种有用的起始策略。
