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Open data
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Basic information
Entry | Database: PDB / ID: 8dw6 | |||||||||
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Title | T4 bacteriophage primosome with single-strand DNA, State 3 | |||||||||
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![]() | REPLICATION/DNA/RNA / ![]() ![]() ![]() | |||||||||
Function / homology | ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Similarity search - Function | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | ![]() ![]() ![]() | |||||||||
![]() | Feng, X. / Li, H. | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Structural basis of the T4 bacteriophage primosome assembly and primer synthesis. Authors: Xiang Feng / Michelle M Spiering / Ruda de Luna Almeida Santos / Stephen J Benkovic / Huilin Li / ![]() Abstract: The T4 bacteriophage gp41 helicase and gp61 primase assemble into a primosome to couple DNA unwinding with RNA primer synthesis for DNA replication. How the primosome is assembled and how the primer ...The T4 bacteriophage gp41 helicase and gp61 primase assemble into a primosome to couple DNA unwinding with RNA primer synthesis for DNA replication. How the primosome is assembled and how the primer length is defined are unclear. Here we report a series of cryo-EM structures of T4 primosome assembly intermediates. We show that gp41 alone is an open spiral, and ssDNA binding triggers a large-scale scissor-like conformational change that drives the ring closure and activates the helicase. Helicase activation exposes a cryptic hydrophobic surface to recruit the gp61 primase. The primase binds the helicase in a bipartite mode in which the N-terminal Zn-binding domain and the C-terminal RNA polymerase domain each contain a helicase-interacting motif that bind to separate gp41 N-terminal hairpin dimers, leading to the assembly of one primase on the helicase hexamer. Our study reveals the T4 primosome assembly process and sheds light on the RNA primer synthesis mechanism. #1: Journal: bioRxiv / Year: 2023 Title: Structural basis of the T4 bacteriophage primosome assembly and primer synthesis. Authors: Xiang Feng / Michelle M Spiering / Ruda de Luna Almeida Santos / Stephen J Benkovic / Huilin Li / ![]() Abstract: The T4 bacteriophage gp41 helicase and gp61 primase assemble into a primosome complex to couple DNA unwinding with RNA primer synthesis for DNA replication. How a primosome is assembled and how the ...The T4 bacteriophage gp41 helicase and gp61 primase assemble into a primosome complex to couple DNA unwinding with RNA primer synthesis for DNA replication. How a primosome is assembled and how the length of the RNA primer is defined in the T4 bacteriophage, or in any model system, are unclear. Here we report a series of cryo-EM structures of T4 primosome assembly intermediates at resolutions up to 2.7 Å. We show that the gp41 helicase is an open spiral in the absence of ssDNA, and ssDNA binding triggers a large-scale scissor-like conformational change that drives the open spiral to a closed ring that activates the helicase. We found that the activation of the gp41 helicase exposes a cryptic hydrophobic primase-binding surface allowing for the recruitment of the gp61 primase. The primase binds the gp41 helicase in a bipartite mode in which the N-terminal Zn-binding domain (ZBD) and the C-terminal RNA polymerase domain (RPD) each contain a helicase-interacting motif (HIM1 and HIM2, respectively) that bind to separate gp41 N-terminal hairpin dimers, leading to the assembly of one primase on the helicase hexamer. Based on two observed primosome conformations - one in a DNA-scanning mode and the other in a post RNA primer-synthesis mode - we suggest that the linker loop between the gp61 ZBD and RPD contributes to the T4 pentaribonucleotide primer. Our study reveals T4 primosome assembly process and sheds light on RNA primer synthesis mechanism. | |||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 574.6 KB | Display | ![]() |
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PDB format | ![]() | 469.2 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 27751MC ![]() 8dtpC ![]() 8dueC ![]() 8duoC ![]() 8dvfC ![]() 8dviC ![]() 8dwjC ![]() 8g0zC ![]() 8gaoC C: citing same article ( M: map data used to model this data |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
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Assembly
Deposited unit | ![]()
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Components
-Protein , 2 types, 7 molecules ABCDEFH
#1: Protein | Mass: 53662.848 Da / Num. of mol.: 6 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() ![]() #3: Protein | | ![]() Mass: 39842.043 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() ![]() ![]() References: UniProt: P04520, ![]() |
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-DNA chain , 2 types, 2 molecules MT
#2: DNA chain | Mass: 3605.356 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) ![]() ![]() |
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#4: DNA chain | Mass: 1536.035 Da / Num. of mol.: 1 / Source method: obtained synthetically / Source: (synth.) ![]() ![]() |
-Non-polymers , 3 types, 11 molecules ![](data/chem/img/AGS.gif)
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#5: Chemical | ChemComp-AGS / #6: Chemical | ChemComp-MG / #7: Chemical | ChemComp-ZN / | |
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-Details
Has ligand of interest | Y |
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-Experimental details
-Experiment
Experiment | Method: ![]() |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: ![]() |
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Sample preparation
Component | Name: Complex of T4 bacteriophage primosome including helicase gp41, primase gp61 and ssDNA/RNA hybrid Type: COMPLEX / Entity ID: #1-#4 / Source: RECOMBINANT | |||||||||||||||||||||||||
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Molecular weight | Experimental value: NO | |||||||||||||||||||||||||
Source (natural) | Organism: ![]() ![]() | |||||||||||||||||||||||||
Source (recombinant) | Organism: ![]() ![]() ![]() | |||||||||||||||||||||||||
Buffer solution | pH: 7.8 Details: 20 mM HEPES pH 7.8, 100 mM NaCl, 10 mM MgCl2 and 2 mM DTT | |||||||||||||||||||||||||
Buffer component |
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Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied![]() ![]() | |||||||||||||||||||||||||
Vitrification![]() | Cryogen name: ETHANE |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source![]() ![]() |
Electron lens | Mode: BRIGHT FIELD![]() |
Image recording | Electron dose: 66 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) |
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Processing
Software | Name: PHENIX / Version: 1.20_4459: / Classification: refinement | ||||||||||||||||||||||||||||||||||||||||||||
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EM software |
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CTF correction![]() | Type: NONE | ||||||||||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry![]() | ||||||||||||||||||||||||||||||||||||||||||||
3D reconstruction![]() | Resolution: 3.5 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 142027 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||||||||||
Atomic model building | Protocol: OTHER / Space: REAL | ||||||||||||||||||||||||||||||||||||||||||||
Atomic model building |
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Refine LS restraints |
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