scholarly journals Crystal Structure of SARS-CoV-2 Main Protease in Complex with the Non-Covalent Inhibitor ML188

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 174
Author(s):  
Gordon J. Lockbaum ◽  
Archie C. Reyes ◽  
Jeong Min Lee ◽  
Ronak Tilvawala ◽  
Ellen A. Nalivaika ◽  
...  

Viral proteases are critical enzymes for the maturation of many human pathogenic viruses and thus are key targets for direct acting antivirals (DAAs). The current viral pandemic caused by SARS-CoV-2 is in dire need of DAAs. The Main protease (Mpro) is the focus of extensive structure-based drug design efforts which are mostly covalent inhibitors targeting the catalytic cysteine. ML188 is a non-covalent inhibitor designed to target SARS-CoV-1 Mpro, and provides an initial scaffold for the creation of effective pan-coronavirus inhibitors. In the current study, we found that ML188 inhibits SARS-CoV-2 Mpro at 2.5 µM, which is more potent than against SAR-CoV-1 Mpro. We determined the crystal structure of ML188 in complex with SARS-CoV-2 Mpro to 2.39 Å resolution. Sharing 96% sequence identity, structural comparison of the two complexes only shows subtle differences. Non-covalent protease inhibitors complement the design of covalent inhibitors against SARS-CoV-2 main protease and are critical initial steps in the design of DAAs to treat CoVID 19.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haixia Su ◽  
Sheng Yao ◽  
Wenfeng Zhao ◽  
Yumin Zhang ◽  
Jia Liu ◽  
...  

AbstractThe ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) urgently needs an effective cure. 3CL protease (3CLpro) is a highly conserved cysteine proteinase that is indispensable for coronavirus replication, providing an attractive target for developing broad-spectrum antiviral drugs. Here we describe the discovery of myricetin, a flavonoid found in many food sources, as a non-peptidomimetic and covalent inhibitor of the SARS-CoV-2 3CLpro. Crystal structures of the protease bound with myricetin and its derivatives unexpectedly revealed that the pyrogallol group worked as an electrophile to covalently modify the catalytic cysteine. Kinetic and selectivity characterization together with theoretical calculations comprehensively illustrated the covalent binding mechanism of myricetin with the protease and demonstrated that the pyrogallol can serve as an electrophile warhead. Structure-based optimization of myricetin led to the discovery of derivatives with good antiviral activity and the potential of oral administration. These results provide detailed mechanistic insights into the covalent mode of action by pyrogallol-containing natural products and a template for design of non-peptidomimetic covalent inhibitors against 3CLpros, highlighting the potential of pyrogallol as an alternative warhead in design of targeted covalent ligands.


2020 ◽  
Author(s):  
Jian Li ◽  
Xuelan Zhou ◽  
Yan Zhang ◽  
Fanglin Zhong ◽  
Cheng Lin ◽  
...  

AbstractMain protease (Mpro, also known as 3CLpro) has a major role in the replication of coronavirus life cycle and is one of the most important drug targets for anticoronavirus agents. Here we report the crystal structure of main protease of SARS-CoV-2 bound to a previously identified Chinese herb inhibitor shikonin at 2.45 angstrom resolution. Although the structure revealed here shares similar overall structure with other published structures, there are several key differences which highlight potential features that could be exploited. The catalytic dyad His41-Cys145 undergoes dramatic conformational changes, and the structure reveals an unusual arrangement of oxyanion loop stabilized by the substrate. Binding to shikonin and binding of covalent inhibitors show different binding modes, suggesting a diversity in inhibitor binding. As we learn more about different binding modes and their structure-function relationships, it is probable that we can design more effective and specific drugs with high potency that can serve as effect SARS-CoV-2 anti-viral agents.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Alice Douangamath ◽  
Daren Fearon ◽  
Paul Gehrtz ◽  
Tobias Krojer ◽  
Petra Lukacik ◽  
...  

Abstract COVID-19, caused by SARS-CoV-2, lacks effective therapeutics. Additionally, no antiviral drugs or vaccines were developed against the closely related coronavirus, SARS-CoV-1 or MERS-CoV, despite previous zoonotic outbreaks. To identify starting points for such therapeutics, we performed a large-scale screen of electrophile and non-covalent fragments through a combined mass spectrometry and X-ray approach against the SARS-CoV-2 main protease, one of two cysteine viral proteases essential for viral replication. Our crystallographic screen identified 71 hits that span the entire active site, as well as 3 hits at the dimer interface. These structures reveal routes to rapidly develop more potent inhibitors through merging of covalent and non-covalent fragment hits; one series of low-reactivity, tractable covalent fragments were progressed to discover improved binders. These combined hits offer unprecedented structural and reactivity information for on-going structure-based drug design against SARS-CoV-2 main protease.


Author(s):  
Jerzy Osipiuk ◽  
Saara-Anne Azizi ◽  
Steve Dvorkin ◽  
Michael Endres ◽  
Robert Jedrzejczak ◽  
...  

ABSTRACTThe number of new cases world-wide for the COVID-19 disease is increasing dramatically, while efforts to contain Severe Acute Respiratory Syndrome Coronavirus 2 is producing varied results in different countries. There are three key SARS-CoV-2 enzymes potentially targetable with antivirals: papain-like protease (PLpro), main protease (Mpro), and RNA-dependent RNA polymerase. Of these, PLpro is an especially attractive target because it plays an essential role in several viral replication processes, including cleavage and maturation of viral polyproteins, assembly of the replicase-transcriptase complex (RTC), and disruption of host viral response machinery to facilitate viral proliferation and replication. Moreover, this enzyme is conserved across different coronaviruses and promising inhibitors have already been discovered for its SARS-CoV variant. Here we report a substantive body of structural, biochemical, and virus replication studies that identify several inhibitors of the enzyme from SARS-CoV-2 in both wild-type and mutant forms. These efforts include the first structures of wild-type PLpro, the active site C111S mutant, and their complexes with inhibitors, determined at 1.60–2.70 Angstroms. This collection of structures provides fundamental molecular and mechanistic insight to PLpro, and critically, illustrates details for inhibitors recognition and interactions. All presented compounds inhibit the peptidase activity of PLpro in vitro, and some molecules block SARS-CoV-2 replication in cell culture assays. These collated findings will accelerate further structure-based drug design efforts targeting PLpro, with the ultimate goal of identifying high-affinity inhibitors of clinical value for SARS-CoV-2.


Author(s):  
Petra Krafcikova ◽  
Jan Silhan ◽  
Radim Nencka ◽  
Evzen Boura

AbstractCOVID-19 pandemic is caused by the SARS-CoV-2 virus that has several enzymes that could be targeted by antivirals including a 2’-O RNA methyltransferase (MTase) that is involved in the viral RNA cap formation; an essential process for RNA stability. This MTase is composed of two nonstructural proteins, the nsp16 catalytic subunit and the activating nsp10 protein. We have solved the crystal structure of the nsp10-nsp16 complex bound to the pan-MTase inhibitor sinefungin in the active site. Based on the structural data we built a model of the MTase in complex with RNA that illustrates the catalytic reaction. A structural comparison to the Zika MTase revealed low conservation of the catalytic site between these two RNA viruses suggesting preparation of inhibitors targeting both these viruses will be very difficult. Together, our data will provide the information needed for structure-based drug design.


2020 ◽  
Author(s):  
Shafi Ullah Khan ◽  
Thet.thet Htar

<p>At present, there are no proven agents for the treatment of 2019 coronavirus disease (COVID-19). The available evidence has not allowed guidelines to clearly recommend any drugs outside the context of clinical trials. One of the most important SARS-CoV-2 protein targets for therapeutics is the 3C-like protease (main protease, Mpro). Here in this study we utilize the recently published 6W63 crystal structure of Mpro complexed with a non-covalent inhibitor X77. Various docking methods FRED, HYBRID, CDOCKER and LEADFINDER tools were benchmark to optimally re-dock the co-crystal ligand within the active site of SARS-COV-2 Mpro. This study was restricted to molecular docking without validation by molecular dynamics simulations. CDOCKER was found to depict the exact binding of co-crystal ligand having lowest RMSD of less than 2 A. Interactions with the SARS-COV-2 Mpro may play a key role in fighting against viruses. Dexamethasone was found to bind with a high affinity to the same sites of the SARS-COV-2 Mpro than the Remdesivir. Dexamethasone was forming six hydrogen bonds compared to the three hydrogen bonds formed by Remdesivir within the active site of SARS-COV-2 Mpro. LEU141, GLY143, HIS163, GLU166, GLN192 were the key amino acid residue of SAR-COV-2 Mpro involved in stabilizing the complex between Dexamethasone and SARS-COV-2 Mpro. The results suggest the effectiveness of Dexamethasone as potent drugs against SARS-CoV-2 since it bind tightly to its Mpro. In addition, the results also suggest that dexamethasone as top antiviral treatments option than the Remdesivir with high potential to fight the SARS-CoV-2.</p>


Author(s):  
Shafi Ullah Khan ◽  
Thet.thet Htar

<p>At present, there are no proven agents for the treatment of 2019 coronavirus disease (COVID-19). The available evidence has not allowed guidelines to clearly recommend any drugs outside the context of clinical trials. One of the most important SARS-CoV-2 protein targets for therapeutics is the 3C-like protease (main protease, Mpro). Here in this study we utilize the recently published 6W63 crystal structure of Mpro complexed with a non-covalent inhibitor X77. Various docking methods FRED, HYBRID, CDOCKER and LEADFINDER tools were benchmark to optimally re-dock the co-crystal ligand within the active site of SARS-COV-2 Mpro. This study was restricted to molecular docking without validation by molecular dynamics simulations. CDOCKER was found to depict the exact binding of co-crystal ligand having lowest RMSD of less than 2 A. Interactions with the SARS-COV-2 Mpro may play a key role in fighting against viruses. Dexamethasone was found to bind with a high affinity to the same sites of the SARS-COV-2 Mpro than the Remdesivir. Dexamethasone was forming six hydrogen bonds compared to the three hydrogen bonds formed by Remdesivir within the active site of SARS-COV-2 Mpro. LEU141, GLY143, HIS163, GLU166, GLN192 were the key amino acid residue of SAR-COV-2 Mpro involved in stabilizing the complex between Dexamethasone and SARS-COV-2 Mpro. The results suggest the effectiveness of Dexamethasone as potent drugs against SARS-CoV-2 since it bind tightly to its Mpro. In addition, the results also suggest that dexamethasone as top antiviral treatments option than the Remdesivir with high potential to fight the SARS-CoV-2.</p>


Author(s):  
Alice Douangamath ◽  
Daren Fearon ◽  
Paul Gehrtz ◽  
Tobias Krojer ◽  
Petra Lukacik ◽  
...  

SummaryCOVID-19, caused by SARS-CoV-2, lacks effective therapeutics. Additionally, no antiviral drugs or vaccines were developed against the closely related coronavirus, SARS-CoV-1 or MERS-CoV, despite previous zoonotic outbreaks. To identify starting points for such therapeutics, we performed a large-scale screen of electrophile and non-covalent fragments through a combined mass spectrometry and X-ray approach against the SARS-CoV-2 main protease, one of two cysteine viral proteases essential for viral replication. Our crystallographic screen identified 71 hits that span the entire active site, as well as 3 hits at the dimer interface. These structures reveal routes to rapidly develop more potent inhibitors through merging of covalent and non-covalent fragment hits; one series of low-reactivity, tractable covalent fragments was progressed to discover improved binders. These combined hits offer unprecedented structural and reactivity information for on-going structure-based drug design against SARS-CoV-2 main protease.


Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1004
Author(s):  
Mahmoud A. El Hassab ◽  
Mohamed Fares ◽  
Mohammed K. Abdel-Hamid Amin ◽  
Sara T. Al-Rashood ◽  
Amal Alharbi ◽  
...  

Since December 2019, the world has been facing the outbreak of the SARS-CoV-2 pandemic that has infected more than 149 million and killed 3.1 million people by 27 April 2021, according to WHO statistics. Safety measures and precautions taken by many countries seem insufficient, especially with no specific approved drugs against the virus. This has created an urgent need to fast track the development of new medication against the virus in order to alleviate the problem and meet public expectations. The SARS-CoV-2 3CL main protease (Mpro) is one of the most attractive targets in the virus life cycle, which is responsible for the processing of the viral polyprotein and is a key for the ribosomal translation of the SARS-CoV-2 genome. In this work, we targeted this enzyme through a structure-based drug design (SBDD) protocol, which aimed at the design of a new potential inhibitor for Mpro. The protocol involves three major steps: fragment-based drug design (FBDD), covalent docking and molecular dynamics (MD) simulation with the calculation of the designed molecule binding free energy at a high level of theory. The FBDD step identified five molecular fragments, which were linked via a suitable carbon linker, to construct our designed compound RMH148. The mode of binding and initial interactions between RMH148 and the enzyme active site was established in the second step of our protocol via covalent docking. The final step involved the use of MD simulations to test for the stability of the docked RMH148 into the Mpro active site and included precise calculations for potential interactions with active site residues and binding free energies. The results introduced RMH148 as a potential inhibitor for the SARS-CoV-2 Mpro enzyme, which was able to achieve various interactions with the enzyme and forms a highly stable complex at the active site even better than the co-crystalized reference.


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