TABLE 1. Top1 mutants studied. Catalytic Top1 mutants (Y723F/Y727F and W736Stop/Y740Stop) can bind but not cleave duplex DNA while DNA binding mutants (T729E/S733E) cannot bind duplex DNA.

32. Tsurutani J, Nitta T, Hirashima T, Komiya T, Uejima H, Tada H, Syunichi N, Tohda A, Fukuoka M, Nakagawa K (2002). Point mutations in the topoisomerase I gene in patients with non-small cell lung cancer treated with irinotecan. Lung Cancer 35(3): 299-304. 10.1016/s0169-5002(01)00425-1

33. Losasso C, Cretaio E, Fiorani P, D'Annessa I, Chillemi G, Benedetti P (2008). A single mutation in the 729 residue modulates human DNA topoisomerase IB DNA binding and drug resistance. Nucleic Acids Res 36(17): 5635-5644. 10.1093/nar/gkn557

44. Redinbo MR, Stewart L, Kuhn P, Champoux JJ, Hol WG (1998). Crystal structures of human topoisomerase I in covalent and noncovalent complexes with DNA. Science 279(5356): 1504-1513. 10.1126/science.279.5356.1504