2IS4

Crystal structure of UvrD-DNA-ADPNP ternary complex

Summary for 2IS4

• Entry DOI: 10.2210/pdb2is4/pdb
• Related: 2IS1 2IS2
• Descriptor: 25-MER, DNA helicase II, MAGNESIUM ION, ... (5 entities in total)
• Functional Keywords: dna helicase, hydrolase-dna complex, hydrolase/dna
• Biological source: Escherichia coli
• Total number of polymer chains: 4
• Total formula weight: 172625.43

Authors

Yang, W.,Lee, J.Y. (deposition date: 2006-10-16, release date: 2007-01-09, Last modification date: 2023-08-30)

Primary citation

Lee, J.Y.,Yang, W.
UvrD helicase unwinds DNA one base pair at a time by a two-part power stroke.
Cell(Cambridge,Mass.), 127:1349-1360, 2006

PubMed Abstract: Helicases use the energy derived from nucleoside triphosphate hydrolysis to unwind double helices in essentially every metabolic pathway involving nucleic acids. Earlier crystal structures have suggested that DNA helicases translocate along a single-stranded DNA in an inchworm fashion. We report here a series of crystal structures of the UvrD helicase complexed with DNA and ATP hydrolysis intermediates. These structures reveal that ATP binding alone leads to unwinding of 1 base pair by directional rotation and translation of the DNA duplex, and ADP and Pi release leads to translocation of the developing single strand. Thus DNA unwinding is achieved by a two-part power stroke in a combined wrench-and-inchworm mechanism. The rotational angle and translational distance of DNA define the unwinding step to be 1 base pair per ATP hydrolyzed. Finally, a gateway for ssDNA translocation and an alternative strand-displacement mode may explain the varying step sizes reported previously.

PubMed: 17190599
DOI: 10.1016/j.cell.2006.10.049

Experimental method

X-RAY DIFFRACTION (2.6 Å)