Researchers have taken the first steps toward understanding how an enzyme repairs DNA.
Enzymes called helicases play a key role in human health, according to Maria Spies, a University of Illinois biochemistry professor.
DNA helicases act as critical components in many molecular machineries orchestrating DNA repair in the cell. she said. Multiple diseases including cancer and aging are associated with malfunctions in these enzymes.
Spies laboratory undertook a recent study of an enzyme, called Rad3, which defines a group of DNA helicases characterized by a unique structural domain containing iron. The findings appear in the Journal of Biological Chemistry.
Helicases are a special category of molecular motors that modify DNA (deoxyribonucleic acid, the fundamental building block of genes and chromosomes). They do so by moving along strands of DNA, much the same way cars move on roads, using an energy-packed molecule, adenosine triphosphate (ATP) as a fuel source.
Their primary function is to unzip double-stranded DNA, allowing replication and repair of the strands.
DNA is a fragile molecule that undergoes dramatic changes when exposed to radiation, ultraviolet light, toxic chemicals or byproducts of normal cellular processes. DNA damage, if not repaired in time, may lead to mutations, cancer or cell death. Many helicases in the Rad3 family are key players in the cells elaborate machinery to prevent and repair such damage. Mutations in the human members of this helicase family impede DNA repair and may contribute to breast cancer, Fanconi Anemia and Xeroderma pigmentosum.
The researchers studied the archaeal version of Rad3. Archaea are microbes whose DNA repair systems are closely related to those of human cells.
(The archaeal Rad3) is a very good representative of a unique family of structurally related DNA repair helicases, all of which have the same motor core and share an unprece
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University of Illinois at Urbana-Champaign