Bxb1 bacteriophage was isolated in the Bronx, NY . It infects Mycobacterium Smegmatis. Its genome is around 50.000 bp and code for 86 proteins . Bxb1 integrase catalyze integration of the phage genome into the GroEL1 gene of M.segmentis, which contains the attB site . Minimal attB, attP,, attL and attR  have been characterized. Excisionase has been identified, is relatively big (28kDa) for a RDF, and is efficient both in vivo and in vitro . In vitro recombination is very efficient ranging a 100% efficiency in 1hour for integration  and for excision . Interestingly the excisionase subunit does not bind DNA and acts stoechiometrically on Bxb1 integrase . The enzyme does not require supercoiled DNA, and can also works with linear products . The enzyme also works well in human, rat, and mouse cells [5, 6].
- att sites:
 Mycobacteriophage Bxb1 integrates into the Mycobacterium smegmatis groEL1 gene. Kim AI, Ghosh P, Aaron MA, Bibb LA, Jain S, Hatfull GF. Mol Microbiol. 2003
 The orientation of mycobacteriophage Bxb1 integration is solely dependent on the central dinucleotide of attP and attB. Ghosh P, Kim AI, Hatfull GF. Mol Cell. 2003 PMID:14636570
 Control of phage Bxb1 excision by a novel recombination directionality factor., Ghosh P. et al, PLoS Biol., 2006. PMID: 16719562.
 Phage Bxb1 integrase mediates highly efficient site-specific recombination in mammalian cells., Russel JP et al., Biotechniques, 2006. PMID:16629393
 A diversity of serine phage integrases mediate site-specific recombination in mammalian cells. Keravala A, Groth AC, Jarrahian S, Thyagarajan B, Hoyt JJ, Kirby PJ, Calos MP. Mol Genet Genomics, 2006 PMID: 16699779