Superfamily 1 helicases

Abstract

Superfamily 1 helicases are nucleic acid motor proteins that couple ATP hydrolysis to translocation along, and concomitant unwinding of, DNA or RNA. This is central to many aspects of cellular DNA and RNA metabolism and, accordingly, they are implicated in a wide range of nucleic acid processing events including DNA replication, recombination and repair as well as many aspects of RNA metabolism. This review discusses our current understanding of the structure, function and mechanism of Superfamily 1 helicases.

Mutational analysis of the functional sites in porcine reproductive and respiratory syndrome virus non-structural protein 10

“…Residue Ala227 of nsp10 has low conservation in these helicases. It most probably corresponds to Tyr in PcrA, Ser in Upf1 and Val in RecD2 (Gilhooly et al, 2013). In arterivirus, the amino acid at this site is strictly limited to Ala (PRRSV, LDV and SHFV) or Val (EAV).…”

“…Motif II in SF1 helicase is characterized by the highly conserved DExx sequence (Gilhooly et al, 2013;Jankowsky, 2011), in which the x represents any amino acid. Residue Ala227 of nsp10 has low conservation in these helicases.…”

Bacterial Transcription as a Target for Antibacterial Drug Development

“…Although the role of helicases in eukaryotic transcription has been studied for many years (reviewed in reference 219), other than Rho, transcription in bacteria is not a process traditionally thought to require the activity of helicases to unwind or rewind DNA/RNA or DNA-RNA hybrids. In E. coli, UvrD is a superfamily 1 (SF 1) helicase involved primarily in nucleotide excision repair, a process whereby various DNA lesions are located and removed (220,221). More recently, it has been shown in E. coli that UvrD is able to bind directly to transcribing RNAP to a level comparable to that for common transcription factors (such as NusA [191]).…”

Molecular and Functional Characterization of RecD, a Novel Member of the SF1 Family of Helicases, from Mycobacterium tuberculosis

“…Purified E. coli RecD is not well behaved in solution unless as a part of the RecBCD complex (7,34). Furthermore, many biochemical and mechanistic studies have been on the intact RecBCD enzyme complex, which is complicated by the fact that it contains two helicase subunits, RecB and RecD (7).…”

“…The unwinding mechanism proposed for SF1 helicases, based on the crystal structures of PcrA and UvrD, has been the subject of much debate because of the absence of direct evidence that monomers can catalyze DNA-unwinding reactions. Indeed, it has been conjectured that either a homodimer or higher order oligomeric form of SF1 helicase(s) is essential for driving efficient DNA unwinding activity (34). Thus, our results showing that MtRecD exists in solution as a homodimer, binds more robustly to Y-shaped DNA structures, and catalyzes ATP-dependent unwinding of DNA substrates in both 5Ј 3 3Ј and 3Ј 3 5Ј directions, albeit with different efficiencies, as well as inhibits RecA activity, are striking.…”