Residues contacting the 3’-end (A) or the 5’-end (B) of the bound ssDNA that were mutated. (C) Table showing ssDNA binding constants and ssDNA-dependent ATPase activity for wildtype DinG and mutants. The equivalent residues in T. acidophilus XPD (taXPD), human XPD (hsXPD), human DDX11 (hsDDX11), human FANCJ (hsFANCJ) and human RTEL1 (hsRTEL1) are listed and those highlighted in bold are directly linked to human disease. Residues in bold have been found to be mutated and confirmed important for protein function or diseased related (for human XPD, DDX11, FANCJ and RTEL1, the related disease is shown in brackets, ‘TTD’, Trichothiodystrophy, ‘XP’, Xeroderma Pigmentosum, ‘WBS’, Warsaw Breakage Syndrome, ‘UCEC’, Uterine Corpus Endometrial Carcinoma, ‘M’, Mixed cancer types, ‘BC’, Breast cancer, ‘BLCA’, Bladder Urothelial Carcinoma). This information was obtained from Krassowski et al. (2018) and Cerami et al. (2012). (D) Comparison of helicase activities of wildtype and mutant DinG proteins. Forked DNA substrate (50 nM) was incubated at various concentrations (0.1, 1 and 10 μM) of enzyme and the products were analysed on 12% native-PAGE. Heat-denatured substrate was run as a positive control.