Cryo-EM structure of the replisome reveals multiple interactions coordinating DNA synthesis

Proc Natl Acad Sci U S A. 2017 Mar 7;114(10):E1848-E1856. doi: 10.1073/pnas.1701252114. Epub 2017 Feb 21.


We present a structure of the ∼650-kDa functional replisome of bacteriophage T7 assembled on DNA resembling a replication fork. A structure of the complex consisting of six domains of DNA helicase, five domains of RNA primase, two DNA polymerases, and two thioredoxin (processivity factor) molecules was determined by single-particle cryo-electron microscopy. The two molecules of DNA polymerase adopt a different spatial arrangement at the replication fork, reflecting their roles in leading- and lagging-strand synthesis. The structure, in combination with biochemical data, reveals molecular mechanisms for coordination of leading- and lagging-strand synthesis. Because mechanisms of DNA replication are highly conserved, the observations are relevant to other replication systems.

Keywords: DNA polymerase; DNA replication; coordination of leading- and lagging-strands synthesis; cryo-EM structure; replisome.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacteriophage T7 / chemistry
  • Bacteriophage T7 / genetics
  • Bacteriophage T7 / ultrastructure
  • Cryoelectron Microscopy
  • DNA / biosynthesis
  • DNA / chemistry*
  • DNA / genetics
  • DNA / ultrastructure
  • DNA Replication / genetics*
  • Multienzyme Complexes / chemistry*
  • Multienzyme Complexes / genetics
  • Multienzyme Complexes / ultrastructure
  • Protein Domains
  • Thioredoxins / chemistry*
  • Thioredoxins / genetics
  • Thioredoxins / ultrastructure


  • Multienzyme Complexes
  • Thioredoxins
  • DNA