Amino acids, the building blocks of proteins, could protect DNA against damages from radiation and certain chemicals, claims an Indian research team1.
Employing computer-based simulation studies, the researchers found that cysteine and tyrosine protect DNA against such damage. The study opens up the possibility of using the amino acids as drugs to check DNA damage that diseases such as aging, cancer and neurodegenerative ailments.
The researchers launched simulation studies to see whether these amino acids could repair guanyl radical protecting DNA. The study found that an electron belonging to sulfur atom of cysteine was completely transferred to the guanyl radical. In addition to electron transfer, cysteine also lost a hydrogen ion to guanyl radical in one step.
In case of tyrosine, this amino acid also donates an electron and a proton to pair the unpaired electron of guanyl radical. These reactions make guanine electronically neutral, thereby retrieving normal guanine.
"This research explains how our living cells are evolved with enzymes or proteins capable of repairing DNA," says lead researcher Nihar Ranjan Jena. The study, throwing light on key amino acids and their mechanism, may help design enzymes outside cells and resulting in anti-cancer drugs, he adds.
The authors of this work are from: Division Molecular Biophysics (B020), Deutsches Krebsforschungszentrum (DKFZ), Im Neuenheimer Feld 580, D - 69120 Heidelberg, Germany, and Department of Physics, Banaras Hindu University, Varanasi, India
