Editing Lambda phage (section)

====Prophage integration====
The integration of phage λ takes place at a special attachment site in the bacterial and phage genomes, called ''att<sup>λ</sup>''. The sequence of the bacterial att site is called ''attB'', between the ''gal'' and ''bio'' operons, and consists of the parts B-O-B', whereas the complementary sequence in the circular phage genome is called ''attP'' and consists of the parts P-O-P'. The integration itself is a sequential exchange (see [[genetic recombination]]) via a [[Holliday junction]] and requires both the phage protein Int and the bacterial protein IHF (''integration host factor''). Both Int and IHF bind to ''attP'' and form an intasome, a DNA-protein-complex designed for [[site-specific recombination]] of the phage and host DNA. The original B-O-B' sequence is changed by the integration to B-O-P'-phage DNA-P-O-B'. The phage DNA is now part of the host's genome.<ref>{{cite journal | vauthors = Groth AC, Calos MP | title = Phage integrases: biology and applications | journal = Journal of Molecular Biology | volume = 335 | issue = 3 | pages = 667–678 | date = January 2004 | pmid = 14687564 | doi = 10.1016/j.jmb.2003.09.082 }}</ref>