@article{mbs:/content/journal/micro/10.1099/00221287-146-11-2855, author = "Partridge, Sally R. and Recchia, Gavin D. and Scaramuzzi, Carol and Collis, Christina M. and Stokes, H. W. and Hall, Ruth M.", title = "Definition of the attI1 site of class 1 integrons", journal= "Microbiology", year = "2000", volume = "146", number = "11", pages = "2855-2864", doi = "https://doi.org/10.1099/00221287-146-11-2855", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-146-11-2855", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "59-be, 59-base element", keywords = "2°rs, secondary recombination site", keywords = "Ap, ampicillin", keywords = "IntI1, integrase of class 1 integrons", keywords = "gene cassettes", keywords = "attI", keywords = "integrase", keywords = "Tp, trimethoprim", keywords = "site-specific recombination", keywords = "Cm, chloramphenicol", keywords = "integron", keywords = "Nx, nalidixic acid", keywords = "Tc, tetracycline", keywords = "5′-CS, 5′ conserved segment", keywords = "Su, sulphamethoxazole", keywords = "Sm, streptomycin", abstract = "Integron-encoded integrases recognize two distinct types of recombination site: attI sites, found in integrons, and members of the 59-base element (59-be) family, found in the integron-associated gene cassettes. The class 1 integron integrase, IntI1, catalyses recombination between attI1 and a 59-be, two 59-be, or two attI1 sites, but events involving two attI1 sites are less efficient than the reactions in which a 59-be participates. The full attI1 site is required for high-efficiency recombination with a 59-be site. It is 65 bp in length and includes a simple site, consisting of a pair of inversely oriented IntI1-binding domains, together with two further directly oriented IntI1-binding sites designated strong and weak. However, a smaller region that contains only the simple site is sufficient to support a lower level of recombination with a complete attI1 partner and the features that determine the orientation of attI1 reside within this region. An unusual reaction between the attI1 site and a 59-be appears to be responsible for the loss of the central region of a 59-be to create a potential fusion of two adjacent gene cassettes.", }