According to their catalytic amino acid, site specific recombinases are divided between two families: Tyrosine recombinases and serines recombinases.
These two classes are well separated and have probably arisen and evoluted separately.
They also differs greatly by their recombination mechanism: "Planar" Holliday Junction resolution for tyrosines recombinases vs Double strand breacks and rotation for serine recombinases.
- small sequence conservation
- catalytic tyrosine in C-terminus
- Holliday junction intermediate
Members and natural functions
- Lambda Integrase: integration/excision of Lambda phage genome
- Cre: excision: dimer reduction in phage P1 plasmid
- FimB/FimE: inversion: alternate gene expression (e.coli fimbrial phase variation)
- FLP: inversion amplification of yeast 2μm plasmid
recombination site structure
Tetramere assembly, DNA inside, with half of the site reactivity: 2 monomers are actives at a time. Holliday junction isomerisation required.
- good sequence conservation
- N-Ter catalytic serine
- Double Strand Breaks and 180° rotation
Members and Natural functions
- Hin: inversion (alternate gene expression Salmonella flagellar phase variation
- Gin, Cin: inversion (alternate gene expresssion of tails fiber proteins in phages Mu and P1)
- PhiC31: integration Streptomyces
- bbx1: integration
- TP901-1: integration/excision of lactococcaltemperate phage TP901-1 in Lactococcus lactis.
- Tn3: resolvase: excision=resolution of cointegrates
- γδ resolvase: idem
Tetramere assembly, DNA outside, 4 breaks (2 DSBs) at the same time,half of the complex 180° make a rotation