Abstract: Journal of Molecular Structure 1230 (2021) 129891 Contents lists available at ScienceDirect Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstr Inhibitory capacity of chloroquine against SARS-COV-2 by effective binding with angiotensin converting enzyme-2 receptor: An insight from molecular docking and MD-simulation studies Nabajyoti Baildya a,∗, Narendra Nath Ghosh b, Asoke P. Chattopadhyay a a b Department of Chemistry, University of Kalyani, Kalyani 741235, India Department of Chemistry, University of Gour Banga, Mokdumpur, Malda, 732103, India a r t i c l e i n f o Article history: Received 22 June 2020 Revised 22 August 2020 Accepted 4 January 2021 Available online 7 January 2021 Keywords: Chloroquine (CLQ) Angiotensin converting enzyme 2 (ACE2) protein Molecular docking MD-simulation a b s t r a c t The main binding site for SARS-COV-2 spike protein in human body is human Angiotensin converting enzyme 2 (ACE2) protein receptor. Herein we present the effect of chloroquine (CLQ) on human ACE2 receptor. Molecular docking studies showed that chloroquine have a docking score is quite high compare to other well known drugs. Furthermore, molecular dynamics (MD) studies with CLQ docked ACE2 results in large fluctuations on RMSD up to 2.3 ns, indicating conformational and rotational changes due to the presence of drug molecule in the ACE2 moiety. Analysis of results showed that CLQ can effect the conformation of human ACE2 receptor. We believed that this work will help researchers to understand better the effect of CLQ on ACE2.