Abstract
The parA system of plasmid R1 consists of hive genes, parM and parR, and a cis-acting centromere-like site parC. The ParM protein exhibits similarity with a superfamily of ATPases that includes actin, hsp70 and hexokinase. ParM was purified to near-homogeneity and assayed for in vitro ATPase activity. The wild-type ParM protein was found to posses ATPase activity. Mutant ParM derivatives that exhibited decreased in vitro ATPase activity were non-fuctional in vivo, indicating that the ATP turnover by ParM is essential for correct plasmid partitioning. The mutant ParM proteins exhibited trans-dominance, suggesting that ParM participates as a structural component of the partitioning apparatus. The ATPase activity of ParM was activated slightly by the presence of ParR and activated to a much greater extent when ParR was bound to the centromere-like parC region. An analysis using the yeast two-hybrid system indicated that ParM and ParR interact, and demonstrated that ParR interacts with itself. Thus our results suggest a direct interaction of ParM and ParR at the natural partition site parC, and that the ATPase activity of ParM is specifically stimulated by this interaction. (C) 1997 Academic Press Limited.
| Original language | English |
|---|---|
| Journal | Journal of Molecular Biology |
| Volume | 269 |
| Issue number | 4 |
| Pages (from-to) | 505-513 |
| Number of pages | 9 |
| ISSN | 0022-2836 |
| DOIs | |
| Publication status | Published - 1997 |
| Externally published | Yes |