Novel zinc finger nuclease created by combining the Cys(2)His(2)- and His(4)-type zinc finger domains.

摘要

To improve the DNA hydrolytic activity of the zinc finger nuclease, we have created a new artificial zinc finger nuclease (ZWH4) by connecting two distinct zinc finger domains possessing different types of Zn(II) binding sites (Cys(2)His(2)- and His(4)-types). The overall fold of ZWH4 is similar to that of the wild-type Sp1 zinc finger (Sp1(zf123)) as revealed by circular dichroism spectroscopy. The gel mobility shift assay demonstrated that ZWH4 binds to the GC box DNA, although the DNA-binding affinity is lower than that of Sp1(zf123). Evidently, ZWH4 hydrolyzes the covalently closed circular plasmid DNA (form I) containing the GC box (pBSGC) to the linear duplex DNA (form III) in the presence of a higher concentration (50 times) of the protein than DNA for a 24-h reaction. Of special interest is the fact that the novel mixed zinc finger protein containing the Cys(2)His(2)- and His(4)-type domains was first created. The present results provide the useful information for the redesign strategy of an artificial nuclease based on the zinc finger motif.