5IKN

Crystal Structure of the T7 Replisome in the Absence of DNA

Summary for 5IKN

• Entry DOI: 10.2210/pdb5ikn/pdb
• Descriptor: DNA-directed DNA polymerase, DNA primase/helicase, Thioredoxin-1 (3 entities in total)
• Functional Keywords: replisome, transferase
• Biological source: Enterobacteria phage T7; More
• Total number of polymer chains: 13
• Total formula weight: 650058.19

Authors

Wallen, J.R.,Ellenberger, T. (deposition date: 2016-03-03, release date: 2016-12-07, Last modification date: 2023-09-27)

Primary citation

Wallen, J.R.,Zhang, H.,Weis, C.,Cui, W.,Foster, B.M.,Ho, C.M.,Hammel, M.,Tainer, J.A.,Gross, M.L.,Ellenberger, T.
Hybrid Methods Reveal Multiple Flexibly Linked DNA Polymerases within the Bacteriophage T7 Replisome.
Structure, 25:157-166, 2017

PubMed Abstract: The physical organization of DNA enzymes at a replication fork enables efficient copying of two antiparallel DNA strands, yet dynamic protein interactions within the replication complex complicate replisome structural studies. We employed a combination of crystallographic, native mass spectrometry and small-angle X-ray scattering experiments to capture alternative structures of a model replication system encoded by bacteriophage T7. Two molecules of DNA polymerase bind the ring-shaped primase-helicase in a conserved orientation and provide structural insight into how the acidic C-terminal tail of the primase-helicase contacts the DNA polymerase to facilitate loading of the polymerase onto DNA. A third DNA polymerase binds the ring in an offset manner that may enable polymerase exchange during replication. Alternative polymerase binding modes are also detected by small-angle X-ray scattering with DNA substrates present. Our collective results unveil complex motions within T7 replisome higher-order structures that are underpinned by multivalent protein-protein interactions with functional implications.

PubMed: 28052235
DOI: 10.1016/j.str.2016.11.019

Experimental method

X-RAY DIFFRACTION (4.802 Å)