The MobM relaxase domain of plasmid pMV158: thermal stability and activity upon Mn2+ and specific DNA binding.

ABSTRACT: Protein MobM, the relaxase involved in conjugative transfer of the streptococcal plasmid pMV158, is the prototype of the MOB(V) superfamily of relaxases. To characterize the DNA-binding and nicking domain of MobM, a truncated version of the protein (MobMN199) encompassing its N-terminal region was designed and the protein was purified. MobMN199 was monomeric in contrast to the dimeric form of the full-length protein, but it kept its nicking activity on pMV158 DNA. The optimal relaxase activity was dependent on Mn(2+) or Mg(2+) cations in a dosage-dependent manner. However, whereas Mn(2+) strongly stabilized MobMN199 against thermal denaturation, no protective effect was observed for Mg(2+). Furthermore, MobMN199 exhibited a high affinity binding for Mn(2+) but not for Mg(2+). We also exami

SUBMITTER: Lorenzo-Diaz F 

PROVIDER: S-EPMC3105389 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature