The conformational changes coupling ATP hydrolysis and translocation in a bacterial DnaB helicase

DnaB helicases are motor proteins that couple ATP-hydrolysis to the loading of the protein onto DNA at the replication fork and to translocation along DNA to separate double-stranded DNA into single strands during replication. Using a network of conformational states, arrested by nucleotide mimics, we herein characterize the reaction coordinates for ATP hydrolysis, DNA loading and DNA translocation using solid-state NMR spectroscopy. AMP-PCP is used as pre-hydrolytic, ADP:AlF4 − as transition state, and ADP as post-hydrolytic ATP mimic. 31P and 13C NMR spectra reveal conformational and dynamic responses to ATP hydrolysis and the resulting DNA loading and translocation with single amino-acid resolution. This allows us to identify residues guiding the DNA translocation process and to explain the high binding affinities for DNA observed for ADP:AlF4 −, which turns out to be optimally preconfigured to bind DNA.

Citation

Thomas Wiegand, Riccardo Cadalbert, Denis Lacabanne, Joanna Timmins, Laurent Terradot, Anja Böckmann, Beat H. Meier. The conformational changes coupling ATP hydrolysis and translocation in a bacterial DnaB helicase Nature Communications. 2019 Jan 03;10

PMID: 30604765

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