Pathways & interactions
Recombinase, conserved site (IPR006118)
Short name: Recombinase_CS
Site-specific recombination plays an important role in DNA rearrangement in prokaryotic organisms. Two types of site-specific recombination are known to occur:
- Recombination between inverted repeats resulting in the reversal of a DNA segment.
- Recombination between repeat sequences on two DNA molecules resulting in their cointegration, or between repeats on one DNA molecule resulting in the excision of a DNA fragment.
Site-specific recombination is characterised by a strand exchange mechanism that requires no DNA synthesis or high energy cofactor; the phosphodiester bond energy is conserved in a phospho-protein linkage during strand cleavage and re-ligation.
Two unrelated families of recombinases are currently known [PMID: 3011407]. The first, called the 'phage integrase' family, groups a number of bacterial, phage and yeast plasmid enzymes. The second [PMID: 2896291], called the 'resolvase' family, groups enzymes which share the following structural characteristics: an N-terminal catalytic and dimerization domain that contains a conserved serine residue involved in the transient covalent attachment to DNA, and a C-terminal helix-turn-helix DNA-binding domain.
The resolvase family is currently known to include the following proteins:
- DNA invertase from Salmonella typhimurium (gene hin). Hin can invert a 900 bp DNA fragment adjacent to a gene for one of the flagellar antigens.
- DNA invertase from Escherichia coli (gene pin).
- DNA invertase from Bacteriophage Mu (gene gin), P1 and P7 (gene cin).
- Resolvases from transposons Tn3, Tn21, Tn501, Tn552, Tn917, Tn1546, Tn1721, Tn2501 and Tn1000 (known as gamma-delta resolvase).
- Resolvase from Clostridium perfringens plasmid pIP404.
- Resolvase from E. coli plasmid R46.
- Resolvase from E. coli plasmid RP4 (gene parA).
- A putative recombinase from Bacillus subtilis (gene cisA) [PMID: 2105293] which plays an important role in sporulation by catalyzing the recombination of genes spoIIIC and spoIVCB to form polymerase sigma-K factor.
- Uvp1, a protein from E. coli plasmid pR which cooperates with the mucAB genes in the DNA repair process and could be a resolvase [PMID: 2550763].
Generally, proteins from the resolvase family have 180 to 200 amino-acid residues, excepting cisA which is much larger (500 residues).