FIG. 3.

Amino acid sequence comparison of the three conserved regions involved in relaxase activity as determined for TraI (27) for the relaxases MobA (Mob), Rlx, and Orf1 from S. aureus plasmids pC221, pS194, and pC223, respectively, MobA (MobA) from pNZ4000, NikB from E. coli plasmid R64 (8), and TraI from the E. coli plasmid RP4. The tyrosine (motif I) and histidine (motif III) residues involved in cleaving-joining reaction, and the serine residue (motif II) involved in DNA binding, are indicated in boldface.