>cd00397 DNA_BRE_C DNA breaking-rejoining enzymes, C-terminal catalytic domain. The DNA breaking-rejoining enzyme superfamily includes type IB topoisomerases and tyrosine recombinases that share the same fold in their catalytic domain containing six conserved active site residues. The best-studied members of this diverse superfamily include human topoisomerase I, the bacteriophage lambda integrase, the bacteriophage P1 Cre recombinase, the yeast Flp recombinase and the bacterial XerD/C recombinases. Their overall reaction mechanism is essentially identical and involves cleavage of a single strand of a DNA duplex by nucleophilic attack of a conserved tyrosine to give a 3' phosphotyrosyl protein-DNA adduct. In the second rejoining step, a terminal 5' hydroxyl attacks the covalent adduct to release the enzyme and generate duplex DNA. The enzymes differ in that topoisomerases cleave and then rejoin the same 5' and 3' termini, whereas a site-specific recombinase transfers a 5' hydroxyl gener

Probab=99.50  E-value=1.2e-14  Score=96.21  Aligned_cols=42  Identities=45%  Similarity=0.765  Sum_probs=40.5

Q ss_pred             CCCCCCHHHHHHHHHHHHCCCHHHHHHHHCCCCHHHHHHHHH
Q ss_conf             216036389999999980899999999848888899999986
Q gi|254780490|r    2 STTAHTLRHSFATHLLSNGGDLRSIQSILGHSRLSTTQIYTN   43 (67)
Q Consensus         2 ~~tpH~lRHt~at~l~~~G~~~~~vq~lLGH~~i~tT~~Y~~   43 (67)
T Consensus       123 ~~~~H~lRht~at~l~~~g~~~~~I~~~lGHs~~~tT~~Y~h  164 (164)
T cd00397         123 GLTPHSLRHTFASALLNAGLDLEAVQDLLGHSSIAMTMRYAH  164 (164)
T ss_pred             CCCCCCCHHHHHHHHHHCCCCHHHHHHHHCCCCHHHHHHCCC
T ss_conf             677566589999999996999999999968999889711839