Zika virus NS4A N-Terminal region (1-48) acts as a cofactor for inducing NTPase activity of NS3 helicase but not NS3 protease.

Zika virus NS4A N-Terminal region (1-48) acts as a cofactor for inducing NTPase activity of NS3 helicase but not NS3 protease.
Arch Biochem Biophys. 2020 Oct 17;:108631
Authors: Kumar D, Kumar A, Bhardwaj T, Giri R
Abstract
Among Flaviviridae, in West Nile virus (WNV) and Hepatitis C virus (HCV), the non-structural protein NS4A modulates the NTPase activity of viral helicases during nucleic acid unwinding through its N-terminal disordered residues (1-50). In HCV, the acidic NS4A also serves as a cofactor for regulating the NS3 protease activity. However, in case of Zika virus (ZIKV), the role of NS4A and its impact on activities of NS3 helicase and protease is not known. In order to elucidate the role of NS4A, we checked the NTPase activity of NS3 helicase and protease activity of NS3 protease in presence of NS4A N-terminal region (residues 1-48) peptide. Our enzyme kinetics results together with binding experiment clearly demonstrate that NS3 helicase in presence of NS4A peptide increased the rate of ATP hydrolysis whereas the protease activity of NS3 protease was not affected. Therefore, like WNV and HCV, our results establish a role of ZIKV NS4A being a cofactor for modulating the NTPase activity of ZIKV NS3 helicase.
PMID: 33080173 [PubMed - as supplied by publisher]

Source: Archives of Biochemistry and Biophysics - October 17, 2020 Category: Biochemistry Authors: Kumar D, Kumar A, Bhardwaj T, Giri R Tags: Arch Biochem Biophys Source Type: research