Biochemical and genetic analysis of nucleic acid-protein interactions
The integration host factor (IHF) of Escherichia coli is a small, sequence-specific DNA-binding protein. The specific and nonspecific DNA binding constants were determined by gel mobility shift assays. The binding constant of IHF for the H$\sp\prime$ site in $\lambda$ attP is 6.8 $\times$ 10$\sp8$ M$\sp{-1}$ and the nonspecific binding constant is 5.8 $\times$ 10$\sp5$ M$\sp{-1}.$ Therefore, the selectivity of IHF binding is about a thousand-fold higher for a specific site over random sequences. To study the molecular determinants specifying IHF binding, a series of 41 oligonucleotides were synthesized containing adenine analogues that modified the surfaces of the major and minor grooves of DNA. The binding constants determined for these analogue-containing H$\sp\prime$ sites revealed that the specific interaction of IHF with its H$\sp\prime$ site involves interactions with both minor and major grooves of the DNA.
Biology, Molecular, Biology, Genetics, Biology, Microbiology
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign