Purification of TAT-ZFNs. (A) Schematic diagram of the TAT-ZFN construct. (B) SDS-PAGE analysis of TAT-ZFNs purified under native conditions. (C) Western blot analysis of expressed TAT-ZFNs using an anti-His antibody. (D) In vitro activity testing of TAT-ZFNs purified under native conditions. The negative control is indicated by “-”. The recognition sequence of Hpy188III is located within the ZFN recognition sequence; therefore, Hpy188III was used as the positive control (+).