The recA protein of Escherichia coli is a DNA-dependent ATPase. In the absence of DNA, the rate of recA protein-promoted ATP hydrolysis drops 2000-fold, exhibiting an apparent k(cat) of approximately 0.015 min-1. This DNA-independent activity can be stimulated to levels approximating those observed with DNA by adding high concentrations (approximately 2M) of a wide variety of salts. The increase in ATP hydrolysis appears to require the minimal interaction of three to four ions with recA protein. The active species in ATP hydrolysis is an aggregate of recA protein. There appears to be little or no cooperativity with respect to ATP binding (Hill coefficient = 1.0). The salt-stimulated ATP hydrolysis reaction is dependent upon Mg2+ ions and is optimal between pH 7.0 and 8.0. In many respects, the high salt concentration appears to be functionally mimicking DNA in activating the recA protein ATPase.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Biological Chemistry|
|State||Published - 1988|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology