Bacterial DNA replication is a complex, multi-step process mediated by an array of proteins that govern it accuracy and efficiency. Crucial for both cell survival and reproduction, any disruption of this otherwise tightly regulated mechanism inevitably leads to cell death [1]. With the antimicrobial resistance on the rise, developing antagonists for the DNA replication proteins emerge as a promising avenue to combat the threat posed by the ever-evolving pathogenic bacteria. Unfortunately, one of the impediments in this path has been the insufficient characterization of the DNA replication machinery, hindering progress in the development of effective antimicrobial strategies [2].
The bacterial primosome (DnaB/DnaG) complex plays a crucial role in the initiation of DNA synthesis by unwinding of the double helix of DNA strands at the replication fork mediated by the ATPase motor helicase protein, DnaB. This unwinding allows each strand of DNA to serve as a template for the RNA polymerase protein, DnaG, to come in and synthesize short RNA primers thus initiating the cascade of DNA synthesis [4-7]. Although partial structure of the E. coli primosome has already been determined by x-ray crystallography [6], there is no structure available of the full-length primosome, yet. This study aims to characterise the structure of full-length primosome of Escherichia coli by employing cryo-EM and computational modelling. This will provide invaluable insights into the mechanism of the primosome and will potentially open up avenues for development of antibiotics tailored to the bacterial replication inhibition, offering new approaches to treat bacterial infections.