Hrobowski Yancey M, Garry Robert F, Michael Scott F
Department of Microbiology and Immunology, Tulane University Health Sciences Center, New Orleans, Louisiana 70112, USA.
Virol J. 2005 Jun 1;2:49. doi: 10.1186/1743-422X-2-49.
Viral fusion proteins mediate cell entry by undergoing a series of conformational changes that result in virion-target cell membrane fusion. Class I viral fusion proteins, such as those encoded by influenza virus and human immunodeficiency virus (HIV), contain two prominent alpha helices. Peptides that mimic portions of these alpha helices inhibit structural rearrangements of the fusion proteins and prevent viral infection. The envelope glycoprotein (E) of flaviviruses, such as West Nile virus (WNV) and dengue virus (DENV), are class II viral fusion proteins comprised predominantly of beta sheets. We used a physio-chemical algorithm, the Wimley-White interfacial hydrophobicity scale (WWIHS) in combination with known structural data to identify potential peptide inhibitors of WNV and DENV infectivity that target the viral E protein. Viral inhibition assays confirm that several of these peptides specifically interfere with target virus entry with 50% inhibitory concentration (IC50) in the 10 microM range. Inhibitory peptides similar in sequence to domains with a significant WWIHS scores, including domain II (IIb), and the stem domain, were detected. DN59, a peptide corresponding to the stem domain of DENV, inhibited infection by DENV (>99% inhibition of plaque formation at a concentrations of <25 microM) and cross-inhibition of WNV fusion/infectivity (>99% inhibition at <25 microM) was also demonstrated with DN59. However, a potent WNV inhibitory peptide, WN83, which corresponds to WNV E domain IIb, did not inhibit infectivity by DENV. Additional results suggest that these inhibitory peptides are noncytotoxic and act in a sequence specific manner. The inhibitory peptides identified here can serve as lead compounds for the development of peptide drugs for flavivirus infection.
病毒融合蛋白通过经历一系列构象变化来介导细胞进入，这些变化导致病毒粒子与靶细胞膜融合。I类病毒融合蛋白，如由流感病毒和人类免疫缺陷病毒（HIV）编码的那些蛋白，包含两个突出的α螺旋。模拟这些α螺旋部分的肽可抑制融合蛋白的结构重排并防止病毒感染。黄病毒（如西尼罗河病毒（WNV）和登革病毒（DENV））的包膜糖蛋白（E）是主要由β折叠组成的II类病毒融合蛋白。我们使用一种物理化学算法，即Wimley-White界面疏水性标度（WWIHS）并结合已知的结构数据，来鉴定靶向病毒E蛋白的WNV和DENV感染性的潜在肽抑制剂。病毒抑制试验证实，其中几种肽特异性干扰靶病毒进入，50%抑制浓度（IC50）在10微摩尔范围内。检测到与具有显著WWIHS分数的结构域（包括结构域II（IIb）和茎结构域）序列相似的抑制性肽。DN59是一种与DENV茎结构域相对应的肽，它抑制DENV感染（在浓度<25微摩尔时对噬斑形成的抑制率>99%），并且DN59对WNV融合/感染性也有交叉抑制作用（在<25微摩尔时抑制率>99%）。然而，一种有效的WNV抑制肽WN83，它对应于WNV E结构域IIb，并不抑制DENV的感染性。其他结果表明，这些抑制性肽无细胞毒性且以序列特异性方式起作用。这里鉴定出的抑制性肽可作为开发用于黄病毒感染的肽类药物的先导化合物。
