Journal article
Ferroplasma acidarmanus RPA2 Facilitates Efficient Unwinding of Forked DNA Substrates by Monomers of FacXPD Helicase
Journal of molecular biology, Vol.383(5), pp.982-998
2008
DOI: 10.1016/j.jmb.2008.09.001
PMID: 18801373
Abstract
The strand-separation activity that is important for many cellular DNA processing machineries is provided by DNA helicases. In order to understand the physiological properties of a helicase acting in the context of its macromolecular machinery, it is imperative to identify the proteins that interact with the enzyme and to analyze how these proteins affect its helicase activities. The archaeal Rad3 helicase XPD (
xeroderma
pigmentosum group
D protein) from
Ferroplasma acidarmanus (
FacXPD) is a superfamily II 5′
→
3′ DNA helicase. Similar to its mammalian homolog working as an integral part of the transcription factor IIH complex,
FacXPD may play an important role in nucleotide excision repair (NER) and transcription initiation. Interaction between
FacXPD and other archaeal NER proteins likely modulates their respective activities. Replication protein A (RPA), a single-stranded DNA (ssDNA)-binding protein, is one of the NER proteins that functionally interact with the human transcription factor IIH complex. There are two RPA proteins in
F. acidarmanus:
FacRPA1, a homodimer of two monomers consisting of two oligonucleotide/oligosaccharide binding folds, and
FacRPA2, a monomer containing a single oligonucleotide/oligosaccharide binding fold. In this study, we analyzed the effect of these ssDNA-binding proteins on
FacXPD helicase activity. We found that
FacRPA2 stimulates DNA unwinding by
FacXPD helicase through a novel mechanism by providing a helix-destabilizing function. In contrast,
FacRPA1 fails to stimulate helicase activity to the same extent as
FacRPA2 and competes with
FacXPD for binding to the ssDNA–double-stranded DNA junction. We conclude that the
FacRPA2-coated fork is a preferred and likely physiological substrate that a monomer of
FacXPD can unwind with a processivity sufficient for expansion of the NER or transcription bubble. We also suggest that duplex melting by a cognate ssDNA-binding protein coordinated with translocation by a helicase may represent a common strategy for duplex unwinding by the Rad3 family of helicases.
Details
- Title: Subtitle
- Ferroplasma acidarmanus RPA2 Facilitates Efficient Unwinding of Forked DNA Substrates by Monomers of FacXPD Helicase
- Creators
- Robert A Pugh - Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USAYuyen Lin - Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USAChelcie Eller - Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USAHaley Leesley - Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USAIsaac K.O Cann - Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USAMaria Spies - Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Resource Type
- Journal article
- Publication Details
- Journal of molecular biology, Vol.383(5), pp.982-998
- Publisher
- Elsevier Ltd
- DOI
- 10.1016/j.jmb.2008.09.001
- PMID
- 18801373
- ISSN
- 0022-2836
- eISSN
- 1089-8638
- Language
- English
- Date published
- 2008
- Academic Unit
- Radiation Oncology; Biochemistry and Molecular Biology
- Record Identifier
- 9984024561402771
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