It has been estimated for
dengue infection that the global population at risk is 3.5 billion people, which makes
dengue an important public health problem. The causative agents of
dengue are dengue viruses. For dengue virus replication, the
dengue virus NS5 protein is of special importance as it has several
enzyme activities important for viral replication. Previous reports of phosphorylation and SUMOylation of
dengue NS5 have shown these
protein modifications have important consequences for NS5 functions. In this report we identify glutathionylation, another reversible post translation modification that impacts on NS5
enzyme activity. Using dengue virus infected cells we employed specific
antibodies and mass spectrometry to identify 3
cysteine residues of NS5
protein as being glutathionylated. Glutathionylation is a post translational protein modification where
glutathione is covalently attached to a
cysteine residue. We showed glutathionylation occurs on 3 conserved
cysteine residues of
dengue NS5. Then we generated two flavivirus recombinant full length
proteins,
dengue NS5 and Zika NS5, to characterize two of the NS5
enzyme activities, namely,
guanylyltransferase and
RNA-dependent RNA polymerase activities. We show glutathionylation of
dengue and Zika NS5 affects
enzyme activities of the two flavivirus
proteins. The data suggests that glutathionylation is a general feature of the
flavivirus NS5 protein and the modification has the potential to modulate several of the NS5
enzyme functions.