Required for efficient mobilization of ColE1 plasmid and is thus essential to promote the specific transfer of the plasmid during conjugation. Probably functions by inducing DNA bending, helping the MbeA relaxase to melt the DNA around the nic site and cleave the phosphodiester bond. Binds specifically double-stranded DNA (dsDNA) containing the ColE1 oriT but does not recognize the inverted repeat (IR). Homodimer. Interacts with MbeA and MbeB to form the relaxosome. Consists of two domains: the N-terminal domain, which contains a predicted ribbon-helix-helix (RHH) DNA-binding domain, and the C-terminal domain, which comprises a signature shared by nicking accessory proteins. To E.coli MbaC and MbkC.