3QPR

HK97 Prohead I encapsidating inactive virally encoded protease


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 5.2 Å
  • R-Value Free: 0.467 
  • R-Value Work: 0.461 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

The Prohead-I structure of bacteriophage HK97: implications for scaffold-mediated control of particle assembly and maturation.

Huang, R.K.Khayat, R.Lee, K.K.Gertsman, I.Duda, R.L.Hendrix, R.W.Johnson, J.E.

(2011) J.Mol.Biol. 408: 541-554

  • DOI: 10.1016/j.jmb.2011.01.016
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Virus capsid assembly requires recruiting and organizing multiple copies of protein subunits to form a closed shell for genome packaging that leads to infectivity. Many viruses encode scaffolding proteins to shift the equilibrium toward particle form ...

    Virus capsid assembly requires recruiting and organizing multiple copies of protein subunits to form a closed shell for genome packaging that leads to infectivity. Many viruses encode scaffolding proteins to shift the equilibrium toward particle formation by promoting intersubunit interactions and stabilizing assembly intermediates. Bacteriophage HK97 lacks an explicit scaffolding protein, but the capsid protein (gp5) contains a scaffold-like N-terminal segment termed the delta domain. When gp5 is expressed in Escherichia coli, the delta domain guides 420 copies of the subunit into a procapsid with T=7 laevo icosahedral symmetry named Prohead-I. Prohead-I can be disassembled and reassembled under mild conditions and it cannot mature further. When the virally encoded protease (gp4) is coexpressed with gp5, it is incorporated into the capsid and digests the delta domain followed by autoproteolysis to produce the metastable Prohead-II. Prohead-I(+P) was isolated by coexpressing gp5 and an inactive mutant of gp4. Prohead-I and Prohead-I(+P) were compared by biochemical methods, revealing that the inactive protease stabilized the capsid against disassembly by chemical or physical stress. The crystal structure of Prohead-I(+P) was determined at 5.2 Å resolution, and distortions were observed in the subunit tertiary structures similar to those observed previously in Prohead-II. Prohead-I(+P) differed from Prohead-II due to the presence of the delta domain and the resulting repositioning of the N-arms, explaining why Prohead-I can be reversibly dissociated and cannot mature. Low-resolution X-ray data enhanced the density of the relatively dynamic delta domains, revealing their quaternary arrangement and suggesting how they drive proper assembly.


    Organizational Affiliation

    Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Major capsid protein
A, B, C, D, E, F, G
385Enterobacteria phage HK97Mutation(s): 0 
Gene Names: 5
Find proteins for P49861 (Enterobacteria phage HK97)
Go to UniProtKB:  P49861
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 5.2 Å
  • R-Value Free: 0.467 
  • R-Value Work: 0.461 
  • Space Group: I 2 3
Unit Cell:
Length (Å)Angle (°)
a = 560.120α = 90.00
b = 560.120β = 90.00
c = 560.120γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
HKL-2000data collection
RAVEmodel building
HKL-2000data reduction
RAVEphasing
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-03-30
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2012-04-11
    Type: Derived calculations
  • Version 1.3: 2013-01-30
    Type: Other