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

Thomas Wiegand (1) , Riccardo Cadalbert (1) , Denis Lacabanne (2) , Joanna Timmins (3) , Laurent L. Terradot (4) , Anja Böckmann (2) , Beat Meier (1)

1 ETH Zürich - Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich]
2 MMSB - Microbiologie moléculaire et biochimie structurale / Molecular Microbiology and Structural Biochemistry
3 IBS - UMR 5075 - Institut de biologie structurale
4 BMSSI - Bases moléculaires et structurales des systèmes infectieux

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:AlF 4 − as transition state, and ADP as post-hydrolytic ATP mimic. 31 P and 13 C 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:AlF 4 − , which turns out to be optimally preconfigured to bind DNA.

Domaines: Biologie structurale [q-bio.BM]; Chimie analytique

Thomas Wiegand, Riccardo Cadalbert, Denis Lacabanne, Joanna Timmins, Laurent L. Terradot, et al.. The conformational changes coupling ATP hydrolysis and translocation in a bacterial DnaB helicase. Nature Communications, 2019, 10 (1), pp.31. ⟨10.1038/s41467-018-07968-3⟩. ⟨hal-02322585⟩