Figure 3.
PfORC1N1–238 binds specifically to telomeric DNA. (A) Schematic diagram of PfORC1N1–238 and PfORC1N1–182. (B) SDS–PAGE analysis of recombinant purified His6-tagged PfORC1N1–238 or PfORC1N1–182 proteins (1 µg each). (C) PfORC1N1–238 but not PfORC1N1–182 binds directly to telomeric DNA as shown by gel retardation assay (asterisk). The position of free probe is indicated. The higher order DNA–protein complexes are shown by ‘double asterisk’. (D) EMSA was performed using radioactive labeled telomeric DNA and purified PfORC1N1–238. Competition was performed using cold telomeric, AT-rich or GC-rich DNA of relatively similar length and varying concentration (1×, 5× and 10×, respectively). The reaction mixtures were separated in PAGE and the gel was dried and autoradiographed subsequently. Telomeric DNA competed most efficiently compared to AT-rich DNA and GC-rich DNA under the similar experimental conditions.