RecA

Recaș (archaically Armag; ; ; ) is a town in Timiș County, Romania. Six villages are administered by the town: Bazoș, Herneacova, Izvin, Nadăș, Petrovaselo, and Stanciova. It received town status in April 2004. Recaș is best known for the wine produced in the surrounding hills.

RecA is a 38 kilodalton protein essential for the repair and maintenance of DNA in bacteria. It functions as a recombinase and strand-exchange protein, catalyzing the central steps of homologous recombination by forming nucleoprotein filaments on single-stranded DNA. Structural and functional homologs to RecA have been found in all kingdoms of life. RecA serves as an archetype for this class of homologous DNA repair proteins. The homologous protein is called RAD51 in eukaryotes and RadA in archaea. RecA has multiple activities, all related to DNA repair. As a recombinase, it mediates ATP-dependent strand exchange between homologous DNA molecules, driving the key pairing and heteroduplex formation steps of recombinational repair. In the bacterial SOS response, it functions as a co-protease in the autocatalytic cleavage of the LexA repressor and the λ repressor. ===Natural transformation=== Natural bacterial transformation involves the transfer of DNA from one bacterium to another (ordinarily of the same species) and the integration of the donor DNA into the recipient chromosome by homologous recombination, a process mediated by the RecA protein. In some bacteria, the recA gene is induced in response to the bacterium becoming competent, the physiological state required for transformation. ==Clinical significance== RecA has been proposed as a potential drug target for bacterial infections. Small molecules that interfere with RecA function have been identified. Since many antibiotics lead to DNA damage, and all bacteria rely on RecA to fix this damage, inhibitors of RecA could be used to enhance the toxicity of antibiotics. Inhibitors of RecA may also delay or prevent the appearance of bacterial drug resistance. ==History== RecA was discovered in 1965 by Alvin J. Clark and Ann Dee Margulies in genetic screens for recombination deficient strains of E. coli. The gene name "rec", first published in 1969¹, was chosen to indicate its involvement in recombination. In 1976, the recA gene was cloned for the first time by Kevin McEntee. Shortly after, the protein was purified for the first time by several groups. Purification of the protein led to a number of breakthroughs on the biochemical properties of RecA. The first crystal structure of RecA was published in 1992¹, nearly 30 years after the protein was discovered. Later research identified related proteins, including RecBCD and RecF.

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