diff --git a/mcsm_analysis/pyrazinamide/scripts/plotting/OR_PS_Ligand_combined_plot.R b/mcsm_analysis/pyrazinamide/scripts/plotting/OR_PS_Ligand_combined_plot.R
index 0a9d254..26919ce 100644
--- a/mcsm_analysis/pyrazinamide/scripts/plotting/OR_PS_Ligand_combined_plot.R
+++ b/mcsm_analysis/pyrazinamide/scripts/plotting/OR_PS_Ligand_combined_plot.R
@@ -243,7 +243,7 @@ theme_set(theme_gray()) # to preserve default theme
 printFile = cowplot::plot_grid(plot_grid(p1, p2
                              , ncol = 1
                              , align = 'v'
-                             , labels = c("a", "b")
+                             , labels = c("(a)", "(b)")
                              , label_size = my_als+5))
 print(printFile)
 dev.off()