Biological and Medicinal Chemistry

Molecular Docking Studies of N-Acetyl Cysteine, Zinc Acetyl Cysteine and Niclosamide on SARS Cov 2 Protease and Its Comparison with Hydroxychloroquine




Respected Sir/Madam


Respected Sir/Madam

Sub: submission of preprint of article to Chemarxiv for online publication.

I am herewith submitting the preprint of an article entitled “Molecular docking studies of N-acetyl cysteine, zinc acetyl cysteine and niclosamide on SARS Cov 2 protease and its comparison with hydroxychloroquine” for possible publication in “Chemarxiv”.

In this article, we have evaluated the binding abilities of N-acetyl cysteine, zinc acetyl cysteine and niclosamide (antiviral drug) with SARS-COV-2 protease. All the four compounds investigated are effective and selectively bind to active sites of main protease. N-acetyl cysteine being a derivative of cysteine interacts with Cys-145, His-163, Gly-143 of COV-2 protease, zinc acetyl cysteine binds to Gly-143, Ser-144, Cys-145, Glu-166 of COV-2 protease and niclosamide bind to Glu-166, Cys-145, His 41 of main protease. The data has been compared with hydroxychloroquine which effectively binds to Cys-145, Glu-166, Arg-188. The binding affinities of N-acetyl cysteine, zinc-acetyl cysteine and niclosamide are -4.24, -4.29 and -7.5 kcal mol-1 while for hydroxychloroquine it is -6.66 kcal mol-1. Niclosamide with its lowest binding energy interacts with His-41 and Cys-145 which may be the first molecule to show such binding interaction. The results indicate that N-acetyl cysteine, zinc-acetyl cysteine and niclosamide can also be explored for the treatment for SARS COV-2 as an alternative for hydroxychloroquine.

I hope that the manuscript will full fill the journal’s requirements and will get accepted for publication.

Thanking you

With regards

Roopa Guthappa

[email protected]


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