1NO1

Structure of truncated variant of B.subtilis SPP1 phage G39P helicase loader/inhibitor protein

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.204 
  • R-Value Observed: 0.206 

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This is version 1.2 of the entry. See complete history. 


Literature

Structural analysis of Bacillus subtilis SPP1 phage helicase loader protein G39P

Bailey, S., Sedelnikova, S.E., Mesa, P., Ayora, S., Waltho, J.P., Ashcroft, A.E., Baron, A.J., Alonso, J.C., Rafferty, J.B.

(2003) J Biol Chem 278: 15304-15312

  • DOI: 10.1074/jbc.M209300200
  • Primary Citation of Related Structures:  
    1NO1

  • PubMed Abstract: 

    • The Bacillus subtilis SPP1 phage-encoded protein G39P is a loader and inhibitor of the phage G40P replicative helicase involved in the initiation of DNA replication. We have carried out a full x-ray crystallographic and preliminary NMR analysis of G39P and functional studies of the protein, including assays for helicase binding by a number of truncated mutant forms, in an effort to improve our understanding of how it both interacts with the helicase and with the phage replisome organizer, G38P ...

    The Bacillus subtilis SPP1 phage-encoded protein G39P is a loader and inhibitor of the phage G40P replicative helicase involved in the initiation of DNA replication. We have carried out a full x-ray crystallographic and preliminary NMR analysis of G39P and functional studies of the protein, including assays for helicase binding by a number of truncated mutant forms, in an effort to improve our understanding of how it both interacts with the helicase and with the phage replisome organizer, G38P. Our structural analyses reveal that G39P has a completely unexpected bipartite structure comprising a folded N-terminal domain and an essentially unfolded C-terminal domain. Although G39P has been shown to bind its G40P target with a 6:6 stoichiometry, our crystal structure and other biophysical characterization data reveal that the protein probably exists predominantly as a monomer in solution. The G39P protein is proteolytically sensitive, and our binding assays show that the C-terminal domain is essential for helicase interaction and that removal of just the 14 C-terminal residues abolishes interaction with the helicase in vitro. We propose a number of possible scenarios in which the flexibility of the C-terminal domain of G39P and its proteolytic sensitivity may have important roles for the function of G39P in vivo that are consistent with other data on SPP1 phage DNA replication.

    Organizational Affiliation: 

    Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.



Macromolecules
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
replisome organizerA, B, C126Bacillus phage SPP1Mutation(s): 0 
Gene Names: 39
UniProt
Find proteins for Q38151 (Bacillus phage SPP1)
Explore Q38151 
Go to UniProtKB:  Q38151
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ38151
Protein Feature View
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  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE		A, B, C L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.204 
  • R-Value Observed: 0.206 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 88.9α = 90
b = 91.3β = 90
c = 48.4γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
SOLVEphasing
REFMACrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-05-06
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Version format compliance