EMD-0359

Single-particle
3.5 Å
EMD-0359 Deposition: 27/11/2018
Map released: 06/03/2019
Last modified: 20/03/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-0359

Structure of bacteriophage T7 E343Q mutant gp4 helicase-primase in complex with ssDNA, dTTP, AC dinucleotide and CTP (form I)

EMD-0359

Single-particle
3.5 Å
EMD-0359 Deposition: 27/11/2018
Map released: 06/03/2019
Last modified: 20/03/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Enterobacteria phage T7
Sample: Bacteriophage T7 gene product 4 (gp4) helicase primase DNA complex I
Fitted models: 6n7n (Avg. Q-score: 0.421)

Deposition Authors: Gao Y , Cui Y
Structures and operating principles of the replisome.
Gao Y , Cui Y , Fox T , Lin S , Wang H , de Val N, Zhou ZH , Yang W
(2019) Science , 363
PUBMED: 30679383
DOI: doi:10.1126/science.aav7003
ISSN: 1095-9203
ASTM: SCIEAS
Abstract:
Visualization in atomic detail of the replisome that performs concerted leading- and lagging-DNA strand synthesis at a replication fork has not been reported. Using bacteriophage T7 as a model system, we determined cryo-electron microscopy structures up to 3.2-angstroms resolution of helicase translocating along DNA and of helicase-polymerase-primase complexes engaging in synthesis of both DNA strands. Each domain of the spiral-shaped hexameric helicase translocates sequentially hand-over-hand along a single-stranded DNA coil, akin to the way AAA+ ATPases (adenosine triphosphatases) unfold peptides. Two lagging-strand polymerases are attached to the primase, ready for Okazaki fragment synthesis in tandem. A β hairpin from the leading-strand polymerase separates two parental DNA strands into a T-shaped fork, thus enabling the closely coupled helicase to advance perpendicular to the downstream DNA duplex. These structures reveal the molecular organization and operating principles of a replisome.