Nonhexameric SF1 DNA Helicases/Translocases

DNA helicases are a class of motor proteins that function to generate the transient single-stranded DNA required as intermediates in DNA and RNA metabolism. These enzymes couple the energy obtained from the binding and hydrolysis of nucleoside 5'-triphosphates (NTP) to perform the work of DNA duplex unwinding (strand separation) and translocation of the helicase along the linear DNA filament and removing other proteins from DNA. Helicases function in a variety of processes including DNA replication, DNA repair, recombination, bacterial conjugation, and are components of eukaryotic transcription complexes. Mutations in enzymes with helicase activity result in a variety of human genetic diseases. This article focuses on the bacterial Rep, UvrD, and PcrA helicases, all members of the SF1 helicase superfamily.