Specialized Nucleoprotein Structures in high‐fidelity DNA transactions

Three proteins used to initiate DNA replication and carry out site‐specific recombination in E. coli generate organized nucleoprotein structures at their target sites. The association of proteins bound at multiple sites on DNA presumably folds or winds the DNA to produce a specific three‐dimensional conformation. This specialized nucleoprotein structure may be a general mechanism for achieving very high fidelity in DNA transactions in which even a rare mistake must be avoided. The overall interaction is more complex than that of prokaryotic transcription regulators studied so far, but might be characteristic of eukaryotic transcription regulators, for which the problem of site‐localization is more difficult.