Wilce, JVivian, JHastings, AdamFolmer, RutgerDuggin, IainWake, R. GerryWilce, MatthewOtting, Gottfried2016-02-241072-8368http://hdl.handle.net/1885/98867The coordinated termination of DNA replication is an important step in the life cycle of bacteria with circular chromosomes, but has only been defined at a molecular level in two systems to date. Here we report the structure of an engineered replication terminator protein (RTP) ot Bacillus subtilis in complex with a 21 base pair DNA by X-ray crystallography at 2.5 Å resolution. We also use NMR spectroscopic titration techniques. This work reveals a novel DNA interaction involving a dimeric 'winged helix' domain protein that differs from predictions. While the two recognition helices of RTP ate in close contact with the B-form DNA major grooves, the 'wings' and N-termini of RTP do not form intimate contacts with the DNA. This structure provides insight into the molecular basis of polar replication fork arrest based on a model of cooperative binding and differential binding affinities of RTP to the two adjacent binding sites in file complete terminator.Keywords: replication terminator protein; unclassified drug; article; Bacillus subtilis; binding affinity; binding site; DNA protein complex; nuclear magnetic resonance spectroscopy; priority journal; protein domain; protein structure; stop codon; X ray crystallogr200110.1038/849342016-02-24