PMID: 25831501 , Related PDB id: 4TMU
Manthei KA, Hill MC, Burke JE, Butcher SE, Keck JL
Structural mechanisms of DNA binding and unwinding in bacterial RecQ helicases.
Proc Natl Acad Sci U S A. 2015 Apr 7;112(14):4292-7. doi:, 10.1073/pnas.1416746112. Epub 2015 Mar 23.
RecQ helicases unwind remarkably diverse DNA structures as key components of many cellular processes. How RecQ enzymes accommodate different substrates in a unified mechanism that couples ATP hydrolysis to DNA unwinding is unknown. Here, the X-ray crystal structure of the Cronobacter sakazakii RecQ catalytic core domain bound to duplex DNA with a 3' single-stranded extension identifies two DNA-dependent conformational rearrangements: a winged-helix domain pivots approximately 90 degrees to close onto duplex DNA, and a conserved aromatic-rich loop is remodeled to bind ssDNA. These changes coincide with a restructuring of the RecQ ATPase active site that positions catalytic residues for ATP hydrolysis. Complex formation also induces a tight bend in the DNA and melts a portion of the duplex. This bending, coupled with translocation, could provide RecQ with a mechanism for unwinding duplex and other DNA structures.