Pure BRCA2

The "cancer" protein is obtained in pure form
Dmitry Safin, Compulenta

Three research groups managed to isolate the BRCA2 protein corresponding to a gene in which mutations are associated with the development of breast and ovarian cancer.

BRCA2 was identified in 1994. It is known that this gene and its related BRCA1 play a key role in repairing damaged DNA. The proteins interacting with BRCA2 have already been isolated in pure form, but the protein itself was not given to scientists; biologists had to work with its fragments or "complete versions" of similar substances synthesized by bacteria or worms. The main problem was the huge size of BRCA2, which includes 3,418 amino acids. In addition, it is very unstable and is usually found in complex with other proteins.

The first scientific group, representing the University of California at Davis (USA), overcame difficulties by attaching a special "label" to BRCA2 — a protein that binds maltose. This made it possible to increase the solubility of the protein and promoted its folding, which, in turn, made the structure more stable. Eventually, BRCA2 was isolated in pure form from human liver epithelial cells.

Colleagues of American biologists also used "tags", but conducted experiments using slightly different methods. The second group, led by Wolf-Dietrich Heyer from the same University of California, expressed the protein in yeast, and the leader of the third group, Stephen West from the London Research Institute (UK), preferred the option of placing the BRCA2 gene in human epithelial cancer cells.

Now that the method of isolating the "full version" of BRCA2 is known, specialists can begin to determine the structure of the protein. They also have the opportunity to investigate mutations in the BRCA2 gene, that is, intentionally change the genetic sequence and monitor how this will affect the functioning of the protein.

Full versions of the reports are published in the journals Nature (Ryan B. Jensen, Aura Carreira & Stephen C. Kowalczykowski, Purified human BRCA2 stimulates RAD51-mediated recombination) and Nature Structural & Molecular Biology (Jie Liu et al., Human BRCA2 protein promotes RAD51 filament formation on RPA-covered single-stranded DNA; Tina Thorslund et al., The breast cancer tumor suppressor BRCA2 promotes the specific targeting of RAD51 to single-stranded DNA).

Prepared based on the materials of Nature News: Alla Katsnelson, Breast cancer protein is finally purified.

Portal "Eternal youth" http://vechnayamolodost.ru24.08.2010