Studies on the Inhibitory Mechanism of Disulfiram and Diethyldithiocarbamate Against MERS Coronavirus Papain-like Protease

• Main Authors: Chih-Hua Hsieh, 謝智華
• Other Authors: Chi-Yuan Chou
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/zmsg3k

碩士 === 國立陽明大學 === 生命科學系暨基因體科學研究所 === 106 === Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by a novel and highly contagious coronavirus (MERS-CoV) that was first identified in Saudi Arabia in 2012 and then quickly spread worldwide. The papain-like protease (PLpro) of MERS-CoV, which is essential for viral maturation, has been regarded as an important antiviral target due to its proteolysis but also deubiquitinating and deISGylating activity. Here, we report that disulfiram is a potential inhibitor against MERS-CoV PLpro, following a noncompetitive mechanism. Disulfiram is a clinical drug for chronic alcoholism by modifying the cysteine residue in the enzyme active site. According to the mutually binding synergistic effect with other inhibitors (MPA and 6TG) we demonstrate that the probable binding site of disulfiram may be on the third other site of MERS-CoV PLpro. Comparison of the crystal structures of MERS-CoV PLpro in the apo form and in complex with disulfiram and DDC during different soaking time (3.5 ~ 4.5 hours) reveal that disulfiram and DDC can be close to zinc fingers. Even 4.5 hours after soaking, the formation of disulfide bond between zinc-bound cysteine and DDC was observed. In our previous study, disulfiram may act as a “zinc ion ejector” to compete the site within zinc fingers of MERS-CoV PLpro, then lead to enzyme inactive because of the loss of zinc ion for stabilizing the structure (Lin et al., 2018). Therefore, the present studies provide a direct structural and biochemical evidence to help us understand the detail binding mechanism and inhibitory effect of disulfiram against MERS-CoV PLpro, which can be used to design a more efficient antiviral drug.