Ken Kitano and colleagues have co-crystallised the RecQ C-terminal (RQC) domain of human WRN bound to a DNA duplex. In their recent Structure paper, they describe how the RQC domain interacts with a blunt end of the duplex and, surprisingly, unpairs a Watson-Crick base pair in the absence of an ATPase domain. The β wing, an extended hairpin motif characteristic of winged-helix motifs, is used as a “separating knife” to wedge between the first and second base pair. However, the recognition helix, a component of helix-turn-helix motifs embedded within DNA grooves, is excluded from the interaction.
These results present a function of the winged-helix motif central to the helicase reaction, and add further paradigmatic insights on the structural biology of RecQ helicases.
Structural Basis for DNA Strand Separation by the Unconventional Winged-Helix Domain of RecQ Helicase WRN
by
Ken Kitano, Sun-Young Kim, and Toshio Hakoshima
Volume 18, Issue 2, 10 February 2010, Pages 177-187
DRUSE 