Binding then bending: A mechanism for wrapping DNA

摘要

DNA bending by proteins appears to be the rule rather than the exception with the topological distortions ranging from tens of degrees to nearly 720° in the nucleosome core. Bending is important in DNA packaging and in regulating diverse cellular processes. The Escherichia coli integration host factor (IHF), discovered as a host protein required for lysogeny by bacteriophage λ, plays both of these roles. IHF is an excellent model system for analyzing the mechanism by which proteins bend DNA by virtue of its cellular functions, sequence specificity, tight binding, and robust protein-induced DNA bending. The studies of Sugimura and Crothers and Ansari and coworkers in a recent issue of PNAS directly follow the time evolution of DNA bending upon IHF binding to show that bending sequentially follows protein binding.