A study using time-resolved cryogenic electron microscopy reveals the swinging lever mechanism of myosin, providing information on the molecular basis behind the production of force and movement by myosin.

Hexameric helicases are nucleotide-driven molecular machines that unwind DNA to initiate replication across all domains of life. Despite decades of intensive study, several critical aspects of their function remain unresolved1: the site and mechanism of DNA strand separation, the mechanics of unwinding propagation, and the dynamic relationship between nucleotide hydrolysis and DNA movement. Here, using cryo-electron microscopy (cryo-EM), we show that the simian virus 40 large tumour antigen (LTag) helicase assembles in the form of head-to-head hexamers at replication origins, melting DNA at two symmetrically positioned sites to establish bidirectional replication forks. Through continuous heterogeneity analysis2, we characterize the conformational landscape of LTag on forked DNA under catalytic conditions, demonstrating coordinated motions that drive DNA translocation and unwinding. We show that the helicase pulls the tracking strand through DNA-binding loops lining the central channel

Pour la première fois, des chercheurs ont pu visualiser le moment précis où commence la réplication de l’ADN. Ce processus essentiel à la vie permet à l’ADN de se diviser et de se multiplier.

Scientists have captured the first detailed 'molecular movie' showing DNA being unzipped at the atomic level -- revealing how cells begin the crucial process of copying their genetic material.

Cryo-electron microscopy structures of DNA helicases in various conformations provide insight into an ATP-hydrolysis-dependent ‘entropy switch’ that drives unwinding of DNA for replication, with proba...

Cryo-electron microscopy structures of DNA helicases in various conformations provide insight into an ATP-hydrolysis-dependent ‘entropy switch’ that drives unwinding of DNA for replication, with proba...

Cryo-electron microscopy structures of DNA helicases in various conformations provide insight into an ATP-hydrolysis-dependent ‘entropy switch’ that drives unwinding of DNA for replication, with probable conservation across viral and eukaryotic systems.