Reconstitution of a Staphylococcal Plasmid-Protein Relaxation Complex In Vitro
AUTOR(ES)
Caryl, Jamie A.
FONTE
American Society for Microbiology
RESUMO
The isolation of plasmid-protein relaxation complexes from bacteria is indicative of the plasmid nicking-closing equilibrium in vivo that serves to ready the plasmids for conjugal transfer. In pC221 and pC223, the components required for in vivo site- and strand-specific nicking at oriT are MobC and MobA. In order to investigate the minimal requirements for nicking in the absence of host-encoded factors, the reactions were reconstituted in vitro. Purified MobA and MobC, in the presence of Mg2+ or Mn2+, were found to nick at oriT with a concomitant phosphorylation-resistant modification at the 5′ end of nic. The position of nic is consistent with that determined in vivo. MobA, MobC, and Mg2+ or Mn2+ therefore represent the minimal requirements for nicking activity. Cross-complementation analyses showed that the MobC proteins possess binding specificity for oriT DNA of either plasmid and are able to complement each other in the nicking reaction. Conversely, nicking by the MobA proteins is plasmid specific. This suggests the MobA proteins may encode the nicking specificity determinant.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=415747Documentos Relacionados
- Plasmid-protein relaxation complexes in Staphylococcus aureus.
- Properties of the relaxation complex of supercoiled deoxyribonucleic acid and protein of R plasmid NR1 in Escherichia coli.
- Stimulation by Cyclic Adenosine Monophosphate of Plasmid Deoxyribonucleic Acid Replication and Catabolite Repression of the Plasmid Deoxyribonucleic Acid-Protein Relaxation Complex
- Transfer of the gonococcal penicillinase plasmid: mobilization in Escherichia coli by IncP plasmids and isolation as a DNA-protein relaxation complex.
- In vitro reconstitution and activity of a C/D box methylation guide ribonucleoprotein complex
