scholarly journals On the role of ATP hydrolysis in RecA protein-mediated DNA strand exchange. II. Four-strand exchanges.

1992 ◽  
Vol 267 (23) ◽  
pp. 16444-16449
Author(s):  
J.I. Kim ◽  
M.M. Cox ◽  
R.B. Inman
Keyword(s):  
Atp Hydrolysis ◽  
Reca Protein ◽  
Strand Exchange ◽  
Dna Strand Exchange ◽  
Dna Strand

scholarly journals RecA Protein from the Extremely Radioresistant Bacterium Deinococcus radiodurans: Expression, Purification, and Characterization

2002 ◽  
Vol 184 (6) ◽  
pp. 1649-1660 ◽  
Author(s):  
Jong-Il Kim ◽  
Ajay K. Sharma ◽  
Stephen N. Abbott ◽  
Elizabeth A. Wood ◽  
David W. Dwyer ◽  
...  
Keyword(s):  
Deinococcus Radiodurans ◽  
Atp Hydrolysis ◽  
Reca Protein ◽  
Strand Exchange ◽  
Exchange Reactions ◽  
Ssdna Binding ◽  
E Coli ◽  
Dna Strand Exchange ◽  
Ssdna Binding Protein ◽  
Dna Strand

ABSTRACT The RecA protein of Deinococcus radiodurans (RecADr) is essential for the extreme radiation resistance of this organism. The RecADr protein has been cloned and expressed in Escherichia coli and purified from this host. In some respects, the RecADr protein and the E. coli RecA (RecAEc) proteins are close functional homologues. RecADr forms filaments on single-stranded DNA (ssDNA) that are similar to those formed by the RecAEc. The RecADr protein hydrolyzes ATP and dATP and promotes DNA strand exchange reactions. DNA strand exchange is greatly facilitated by the E. coli SSB protein. As is the case with the E. coli RecA protein, the use of dATP as a cofactor permits more facile displacement of bound SSB protein from ssDNA. However, there are important differences as well. The RecADr protein promotes ATP- and dATP-dependent reactions with distinctly different pH profiles. Although dATP is hydrolyzed at approximately the same rate at pHs 7.5 and 8.1, dATP supports an efficient DNA strand exchange only at pH 8.1. At both pHs, ATP supports efficient DNA strand exchange through heterologous insertions but dATP does not. Thus, dATP enhances the binding of RecADr protein to ssDNA and the displacement of ssDNA binding protein, but the hydrolysis of dATP is poorly coupled to DNA strand exchange. The RecADr protein thus may offer new insights into the role of ATP hydrolysis in the DNA strand exchange reactions promoted by the bacterial RecA proteins. In addition, the RecADr protein binds much better to duplex DNA than the RecAEc protein, binding preferentially to double-stranded DNA (dsDNA) even when ssDNA is present in the solutions. This may be of significance in the pathways for dsDNA break repair in Deinococcus.

scholarly journals Characterization of an ATP-dependent DNA strand transferase from human cells.

1987 ◽  
Vol 7 (9) ◽  
pp. 3124-3130 ◽  
Author(s):  
D Ganea ◽  
P Moore ◽  
L Chekuri ◽  
R Kucherlapati
Keyword(s):  
Dna Sequences ◽  
Atp Hydrolysis ◽  
Reca Protein ◽  
Strand Exchange ◽  
Cell Nuclei ◽  
In Vitro Recombination ◽  
Dna Strand ◽  
Exchange Activity

We have characterized an enzymatic activity from human cell nuclei which is capable of catalyzing strand exchange between homologous DNA sequences. The strand exchange activity was Mg2+ dependent and required ATP hydrolysis. In addition, it was capable of promoting reannealing of homologous DNA sequences and could form nucleoprotein networks in a fashion reminiscent of purified bacterial RecA protein. Using an in vitro recombination assay, we also showed that the strand exchange activity was biologically important. The factor(s) responsible for the activity has been partially purified.

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