Giuseppe
Emeritus
A noncovalent class of papain-like protease/deubiquitinase inhibitors blocks SARS virus replication ? PNAS
A noncovalent class of papain-like protease/deubiquitinase inhibitors blocks SARS virus replication
1. Kiira Ratiaa, 2. Scott Pegana, 3. Jun Takayamab, 4. Katrina Sleemanc, 5. Melissa Coughlind, 6. Surendranath Balijic, 7. Rima Chaudhuria,e, 8. Wentao Fua, 9. Bellur S. Prabhakard, 10. Michael E. Johnsona, 11. Susan C. Bakerc, 12. Arun K. Ghoshc,1, and 13. Andrew D. Mesecarc,1
Author Affiliations
1. aCenter for Pharmaceutical Biotechnology and Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, IL 60607;
2. bDepartments of Chemistry and Medicinal Chemistry, Purdue University, West Lafayette, IN 47907;
3. cDepartment of Microbiology and Immunology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153;
4. dDepartment of Microbiology and Immunology, University of Illinois, Chicago, IL 60607; and
5. eDepartment of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607 1.
Edited by Gregory A. Petsko, Brandeis University, Waltham, MA, and approved September 12, 2008 (received for review May 29, 2008)
Abstract
We report the discovery and optimization of a potent inhibitor against the papain-like protease (PLpro) from the coronavirus that causes severe acute respiratory syndrome (SARS-CoV).
This unique protease is not only responsible for processing the viral polyprotein into its functional units but is also capable of cleaving ubiquitin and ISG15 conjugates and plays a significant role in helping SARS-CoV evade the human immune system.
We screened a structurally diverse library of 50,080 compounds for inhibitors of PLpro and discovered a noncovalent lead inhibitor with an IC50 value of 20 μM, which was improved to 600 nM via synthetic optimization.
The resulting compound, GRL0617, inhibited SARS-CoV viral replication in Vero E6 cells with an EC50 of 15 μM and had no associated cytotoxicity.
The X-ray structure of PLpro in complex with GRL0617 indicates that the compound has a unique mode of inhibition whereby it binds within the S4-S3 subsites of the enzyme and induces a loop closure that shuts down catalysis at the active site.
These findings provide proof-of-principle that PLpro is a viable target for development of antivirals directed against SARS-CoV, and that potent noncovalent cysteine protease inhibitors can be developed with specificity directed toward pathogenic deubiquitinating enzymes without inhibiting host DUBs.
* ubiquitin-specific protease
* noncovalent cysteine protease inhibitor
* severe acute respiratory syndrome antiviral
* X-ray structureFootnotes
* 1To whom correspondence may be addressed. E-mail: akghosh@purdue.edu or mesecar@uic.edu
* Author contributions: K.R., M.E.J., S.C.B., A.K.G., and A.D.M. designed research; K.R., S.P., J.T., K.S., M.C., S.B., R.C., and W.F. performed research; J.T., B.S.P., and A.K.G. contributed new reagents/analytic tools; K.R., S.P., K.S., M.E.J., S.C.B., A.K.G., and A.D.M. analyzed data; and K.R., J.T., S.C.B., A.K.G., and A.D.M. wrote the paper.
* The authors declare no conflict of interest.
* This article is a PNAS Direct Submission.
* Data deposition: The atomic coordinates for the crystal structure of the PLpro-inhibitor complex have been deposited with the Research Collaboratory for Structural Bioinformatics Protein Data Bank (accession nos. 3E9S and RCSB049054).
* This article contains supporting information online at www.pnas.org/cgi/content/full/0805240105/DCSupplemental.
* ? 2008 by The National Academy of Sciences of the USA
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<cite cite="http://www.pnas.org/content/105/42/16119.short?rss=1">A noncovalent class of papain-like protease/deubiquitinase inhibitors blocks SARS virus replication ? PNAS</cite>1. Kiira Ratiaa, 2. Scott Pegana, 3. Jun Takayamab, 4. Katrina Sleemanc, 5. Melissa Coughlind, 6. Surendranath Balijic, 7. Rima Chaudhuria,e, 8. Wentao Fua, 9. Bellur S. Prabhakard, 10. Michael E. Johnsona, 11. Susan C. Bakerc, 12. Arun K. Ghoshc,1, and 13. Andrew D. Mesecarc,1
Author Affiliations
1. aCenter for Pharmaceutical Biotechnology and Department of Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, IL 60607;
2. bDepartments of Chemistry and Medicinal Chemistry, Purdue University, West Lafayette, IN 47907;
3. cDepartment of Microbiology and Immunology, Loyola University Chicago Stritch School of Medicine, Maywood, IL 60153;
4. dDepartment of Microbiology and Immunology, University of Illinois, Chicago, IL 60607; and
5. eDepartment of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607 1.
Edited by Gregory A. Petsko, Brandeis University, Waltham, MA, and approved September 12, 2008 (received for review May 29, 2008)
Abstract
We report the discovery and optimization of a potent inhibitor against the papain-like protease (PLpro) from the coronavirus that causes severe acute respiratory syndrome (SARS-CoV).
This unique protease is not only responsible for processing the viral polyprotein into its functional units but is also capable of cleaving ubiquitin and ISG15 conjugates and plays a significant role in helping SARS-CoV evade the human immune system.
We screened a structurally diverse library of 50,080 compounds for inhibitors of PLpro and discovered a noncovalent lead inhibitor with an IC50 value of 20 μM, which was improved to 600 nM via synthetic optimization.
The resulting compound, GRL0617, inhibited SARS-CoV viral replication in Vero E6 cells with an EC50 of 15 μM and had no associated cytotoxicity.
The X-ray structure of PLpro in complex with GRL0617 indicates that the compound has a unique mode of inhibition whereby it binds within the S4-S3 subsites of the enzyme and induces a loop closure that shuts down catalysis at the active site.
These findings provide proof-of-principle that PLpro is a viable target for development of antivirals directed against SARS-CoV, and that potent noncovalent cysteine protease inhibitors can be developed with specificity directed toward pathogenic deubiquitinating enzymes without inhibiting host DUBs.
* ubiquitin-specific protease
* noncovalent cysteine protease inhibitor
* severe acute respiratory syndrome antiviral
* X-ray structureFootnotes
* 1To whom correspondence may be addressed. E-mail: akghosh@purdue.edu or mesecar@uic.edu
* Author contributions: K.R., M.E.J., S.C.B., A.K.G., and A.D.M. designed research; K.R., S.P., J.T., K.S., M.C., S.B., R.C., and W.F. performed research; J.T., B.S.P., and A.K.G. contributed new reagents/analytic tools; K.R., S.P., K.S., M.E.J., S.C.B., A.K.G., and A.D.M. analyzed data; and K.R., J.T., S.C.B., A.K.G., and A.D.M. wrote the paper.
* The authors declare no conflict of interest.
* This article is a PNAS Direct Submission.
* Data deposition: The atomic coordinates for the crystal structure of the PLpro-inhibitor complex have been deposited with the Research Collaboratory for Structural Bioinformatics Protein Data Bank (accession nos. 3E9S and RCSB049054).
* This article contains supporting information online at www.pnas.org/cgi/content/full/0805240105/DCSupplemental.
* ? 2008 by The National Academy of Sciences of the USA
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