Jha, V. and Nagender Rao, R. and Janardhan, S. and Raman, Rajeev and Sastry, G.N. and Sharma, Vartika and Subba Rao, J. and Kumar, Dhiraj and Mukhopadhyay, Sangita (2019) Uncovering Structural and Molecular Dynamics of ESAT-6:β2M Interaction: Asp53 of Human β2-Microglobulin Is Critical for the ESAT-6:β2M Complexation. The Journal of Immunology, 203 (7). pp. 1918-1929. ISSN 0022-1767

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Abstract

ESAT-6 is a small secreted protein of Mycobacterium tuberculosis involved in the ESAT-6 secretion system (ESX-1)-mediated virulence and pathogenesis. The protein interacts with β2M, causing downregulation of MHC class I Ag presentation, which could be one of the mechanisms by which it favors increased survival of the bacilli inside the host. In an earlier study, we have shown that the C-terminal region of ESAT-6 is crucial for its interaction with β2M. However, the interface of β2M involved in interaction with ESAT-6 and detailed physicochemical changes associated with ESAT-6:β2M complexation are not fully defined. In this study, using computational and site-directed mutagenesis studies, we demonstrate the presence of strong noncovalent hydrophobic interactions between ESAT-6 and β2M in addition to the vital hydrogen bonding between the aspartate residue (Asp53) of β2M and methionine (Met93) of ESAT-6. Docking-based high-throughput virtual screening followed by 16-point screening on microscale thermophoresis resulted in the identification of two potent inhibitors (SM09 and SM15) that mask the critical Met93 residue of ESAT-6 that is required for ESAT-6:β2M interaction and could rescue cell surface expression of β2M and HLA in human macrophages as well as MHC class I Ag presentation suppressed by ESAT-6 in peritoneal macrophages isolated from C57BL/6 mice. Both SM09 and SM15 significantly inhibited intracellular survival of M. tuberculosis in human macrophages. Further, we characterized the physicochemical properties involved in the ESAT-6:β2M complexation, which may help in understanding host-pathogen interactions

Item Type:	Article
Depositing User:	Users 2 not found.
Date Deposited:	10 Sep 2019 13:18
Last Modified:	17 Oct 2019 08:53
URI:	http://cdfd.sciencecentral.in/id/eprint/919

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