Electrostatic calculations and model‐building suggest that DNA bound to CAP is sharply bent

Publisher Website
Google Scholar
Abstract
Two observations suggest that DNA, upon binding to E. coli catabolite gene activator protein (CAP), is sharply bent by a total angle of at least 100–150 degrees: (1) The electrostatic protential field of CAP shows regions of positive potential that from a ramp on 3 sides of the protein. (2) The DNA binding site size as determined by DNA ethylation interference with binding, (Majors: “Control of the E. coli Lac Operon at the Molecular Level.” Ph.D. Thesis, Harvard University, Cambridge, 1977) and by relative affinities of DNA fragments of various lengths (Liu-Johnson et al.: Cell 47:995–1005, 1986) requires severe bending of the DNA to maintain its favorable electrostatic contact with the protein.