Structural dynamics of DNA unwinding by a replicative helicase.

ABSTRACT: 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

SUBMITTER: Shahid T 

PROVIDER: S-EPMC12043514 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature