For M13 replication assay, 250 mM of single primed M13mp18 ssDNA was incubated with/without 2 mM TcaR protein in the reaction mixture (20 ml) containing 25 unit Klenow fragment, 25 mM NaCl, 7 mM MgCl 2 , 1 mM EDTA, and 0.5 mM DTT for 3 min at 30uC to allow replication complexes to assemble at the primer template junction [45, 46] . Replication was allowed to proceed by addition of 60 mM dNTP. After incubation at 30uC for 30 min, the reactions were terminated by addition of 10 mM Tris-HCl, 5 mM EDTA, 0.5% SDS, and 50 mg of proteinase K (with total volume of 20 ml) and incubated at 50uC for 1 h. Conventional electrophoresis was then performed to verify the result of DNA replication (20-cm 0.8% agarose gel, 15 mA, 0.5X TBE buffer). The bands are visualized using SYBR Green I nucleic acid gel stain (Invitrogen) and quantified by Quantify One (BIO-RAD, USA).