Conserved helicase domain of human RecQ4 is required for strand annealing-independent DNA unwinding

Research output: Contribution to journalJournal articleResearchpeer-review

Marie L Rossi, Avik K Ghosh, Tomasz Kulikowicz, Deborah L Croteau, Vilhelm A Bohr

Humans have five members of the well conserved RecQ helicase family: RecQ1, Bloom syndrome protein (BLM), Werner syndrome protein (WRN), RecQ4, and RecQ5, which are all known for their roles in maintaining genome stability. BLM, WRN, and RecQ4 are associated with premature aging and cancer predisposition. Of the three, RecQ4's biological and cellular roles have been least thoroughly characterized. Here we tested the helicase activity of purified human RecQ4 on various substrates. Consistent with recent results, we detected ATP-dependent RecQ4 unwinding of forked duplexes. However, our results provide the first evidence that human RecQ4's unwinding is independent of strand annealing, and that it does not require the presence of excess ssDNA. Moreover, we demonstrate that a point mutation of the conserved lysine in the Walker A motif abolished helicase activity, implying that not the N-terminal portion, but the helicase domain is solely responsible for the enzyme's unwinding activity. In addition, we demonstrate a novel stimulation of RecQ4's helicase activity by replication protein A, similar to that of RecQ1, BLM, WRN, and RecQ5. Together, these data indicate that specific biochemical activities and protein partners of RecQ4 are conserved with those of the other RecQ helicases.
Original languageEnglish
JournalDNA Repair
Volume9
Issue number7
Pages (from-to)796-804
Number of pages9
ISSN1568-7864
DOIs
Publication statusPublished - 1 Jul 2010

    Research areas

  • Amino Acid Motifs, Cell Nucleus, Conserved Sequence, DNA, DNA Repair, Humans, Lysine, Nucleic Acid Conformation, Point Mutation, Protein Structure, Tertiary, RecQ Helicases, Substrate Specificity

ID: 33492248