Chikungunya virus (CHIKV), a mosquito-borne pathogenic virus that reemerged and caused epidemic in the Indian Ocean island of La Réunion, is a potential public health threat. Currently there is no antiviral drug or vaccine commercially available for the treatment of chikungunya fever, which necessitates the urge for an effective antiviral therapy for chikungunya treatment. In the present study, a FRET based protease assay was used to analyze the proteolytic activity of chikungunya nsP2 protease (CHIKV nsP2pro) - an essential viral enzyme, with fluorogenic substrate peptide. This protease assay was used to assess the inhibitory activity of Pep-I (MMsINC® database ID MMs03131094) and Pep-II (MMsINC® database ID MMs03927237), peptidomimetic compounds identified in a previous study by our group. Both compounds inhibited CHIKV nsP2pro with half maximal inhibition concentration (IC₅₀) values of ∼34 μM and ∼42 μM, respectively. Kinetic studies showed that the inhibition constant (K_i) value is 33.34±2.53 μM for Pep-I and 45.89±4.38 μM for Pep-II. Additionally, these two compounds significantly inhibited CHIKV replication in BHK-21 cells at concentrations much lower than their cytotoxic concentrations. Intriguingly, these compounds did not show inhibitory effect on Sindbis virus. This suggests that Pep-I and Pep-II compounds identified as CHIKV nsP2 substrate peptidomimetics, specifically inhibit CHIKV replication.

基孔肯雅病毒（CHIKV）是蚊子传播的病原性病毒，它在印度洋拉留尼昂岛重新出现并引起流行，是潜在的公共卫生威胁。目前，尚无可商购的抗病毒药物或疫苗可用于治疗基孔肯雅热，这促使人们迫切需要针对基孔肯雅热的有效抗病毒治疗。在本研究中，基于FRET的蛋白酶检测用于分析基孔肯雅nsP2蛋白酶（CHIKV nsP2pro）（一种必需的病毒酶）与荧光底物肽的蛋白水解活性。该蛋白酶测定法用于评估Pep-I（MMsINC®数据库ID MMs03131094）和Pep-II（MMsINC®数据库ID MMs03927237）的抑制活性，这是我们小组先前在研究中鉴定的拟肽化合物。₅₀）分别为〜34μM和〜42μM。动力学研究表明，Pep-I的抑制常数（K _i）值为33.34±2.53μM，Pep-II的抑制常数为45.89±4.38μM。另外，这两种化合物以比其细胞毒性浓度低得多的浓度显着抑制BHK-21细胞中的CHIKV复制。有趣的是，这些化合物对辛德比斯病毒没有抑制作用。这表明被鉴定为CHIKV nsP2底物拟肽的Pep-I和Pep-II化合物特异性抑制CHIKV复制。