Biochemical, structural and functional analysis of an engineered DNA architectural protein.
Date of Issue2007
School of Biological Sciences
As a DNA architectural protein from E. coli, integration host factor (IHF) can bind and bend DNA in a sequence specific manner. It plays an essential role in a variety of DNA transactions including recombination, transcription and replication. IHF’s ability of concerted binding to and bending of DNA is key to its biological function. Here we report the design, characterization, and application of a single polypeptide chain IHF, termed scIHF2. In a novel approach for protein engineering, we inserted almost the entire a subunit of heterodimeric IHF into the ? subunit at peptide bond Q39/G40 via two short linkers. DNA-binding and -bending assays revealed that the purified wild-type IHF and scIHF2 behave very similarly. Further, scIHF2 is required for site-specific integrative recombination by phage ? integrase and for pSC101 replication in a ?IHF E. coli host. We also demonstrate that scIHF2 is stably expressed in HeLa cells and localized primarily in the cell nucleus, and that it can render cells sensitive to the chemotherapeutic drug cisplatin. Hence, scIHF2 may be used as a novel regulatory co-factor for recombination or other DNA transactions in mammalian cells, and provides a possible target for studies on anti-cancer reagents.
Nanyang Technological University