Comparative Structural and Functional Analysis of Wild-Type and C271A Mutant Forms of Severe Acute Respiratory Syndrome Coronavirus Papain-Like Protease
碩士 === 淡江大學 === 化學學系碩士班 === 106 === The papain-like proteases of the SARS and MERS coronaviruses (SARS-CoV and MERS-CoV PLpros) are vital to viral maturation and therefore are promising antiviral drug targets. A recent study suggests that the alcohol-aversion drug disulfiram inhibits SARS-CoV PLpro...
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| Format: | Others |
| Language: | en_US |
| Published: |
2018
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| Online Access: | http://ndltd.ncl.edu.tw/handle/2r8798 |
| Summary: | 碩士 === 淡江大學 === 化學學系碩士班 === 106 === The papain-like proteases of the SARS and MERS coronaviruses (SARS-CoV and MERS-CoV PLpros) are vital to viral maturation and therefore are promising antiviral drug targets. A recent study suggests that the alcohol-aversion drug disulfiram inhibits SARS-CoV PLpro by a competitive mechanism but MERS-CoV PLpro by a non-competitive mechanism, and a recently published docking model shows blocking-loop residue C271 of SARS-CoV PLpro interacting with disulfiram at a distance of 4.0 Å. Because MERS-CoV PLpro has an alanine rather than a cysteine residue at the analogous position, we performed a series of comparative assays of wild-type and C271A mutant forms of SARS-CoV PLpro to investigate whether this difference in modes of inhibition might be related to this difference in residues at the relevant position. Steady-state kinetic analysis showed a 2.5-fold increase in IC50 value for disulfiram for the mutant in comparison to the wild-type form of the enzyme, and circular dichroism and analytical ultracentrifugation assays showed no difference in secondary or quaternary structure that would account for the difference in IC50 values. We conclude that the presence of a cysteine residue at position 271 in SARS-CoV PLpro in contrast to its absence at the analogous position in MERS-CoV PLpro may explain disulfiram’s different modes of inhibition of the two enzymes. Further confirmation of these findings awaits crystallographic evidence.
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