Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Cyclic - C3  (3D View)
Global Stoichiometry: Homo 3-mer - A3 

Biological assembly 1 assigned by authors and generated by PISA (software)

Biological Assembly 2  

 3D View: Structure | Electron Density

Global Symmetry: Cyclic - C3  (3D View)
Global Stoichiometry: Homo 3-mer - A3 

Biological assembly 2 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 108.37 kDa 
• Atom Count: 7907 
• Residue Count: 874 
• Unique protein chains: 1

1QU1

CRYSTAL STRUCTURE OF EHA2 (23-185)

• DOI: 10.2210/pdb1QU1/pdb

• Classification: VIRAL PROTEIN
• Organism(s): Influenza A virus
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 1999-07-05 Released: 2000-01-05 
• Deposition Author(s): Chen, J., Skehel, J.J., Wiley, D.C.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.90 Å
• R-Value Free: 0.250 
• R-Value Work: 0.229 
• R-Value Observed: 0.229 

Literature

N- and C-terminal residues combine in the fusion-pH influenza hemagglutinin HA(2) subunit to form an N cap that terminates the triple-stranded coiled coil.

Chen, J., Skehel, J.J., Wiley, D.C.

(1999) Proc Natl Acad Sci U S A 96: 8967-8972

• PubMed: 10430879 
• DOI: 10.1073/pnas.96.16.8967
• Primary Citation of Related Structures:  
  1QU1


• PubMed Abstract: 
  

The structure of a stable recombinant ectodomain of influenza hemagglutinin HA(2) subunit, EHA(2) (23-185), defined by proteolysis studies of the intact bacterial-expressed ectodomain, was determined to 1.9-A resolution by using x-ray crystallography. The structure reveals a domain composed of N- and C-terminal residues that form an N cap terminating both the N-terminal alpha-helix and the central coiled coil. The N cap is formed by a conserved sequence, and part of it is found in the neutral pH conformation of HA. The C-terminal 23 residues of the ectodomain form a 72-A long nonhelical structure ordered to within 7 residues of the transmembrane anchor. The structure implies that continuous alpha helices are not required for membrane fusion at either the N or C termini. The difference in stability between recombinant molecules with and without the N cap sequences suggests that additional free energy for membrane fusion may become available after the formation of the central triple-stranded coiled coil and insertion of the fusion peptide into the target membrane.

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Organizational Affiliation: 

Department of Cellular and Molecular Biology, Howard Hughes Medical Institute, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
PROTEIN (INFLUENZA RECOMBINANT HA2 CHAIN)	A, B, C, D, E, F	155	Influenza A virus	Mutation(s): 0
Find proteins for P03437 (Influenza A virus (strain A/Aichi/2/1968 H3N2)) Explore P03437  Go to UniProtKB:  P03437

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.90 Å
• R-Value Free: 0.250 
• R-Value Work: 0.229 
• R-Value Observed: 0.229 
• Space Group: C 1 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 113.241	α = 90
b = 48.877	β = 103.26
c = 221.303	γ = 90

Software Package:

Software Name	Purpose
DENZO	data reduction
SCALEPACK	data scaling
AMoRE	phasing
CNS	refinement

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1999-07-05 
• Released Date: 2000-01-05 
Deposition Author(s): Chen, J., Skehel, J.J., Wiley, D.C.

Revision History 

• Version 1.0: 2000-01-05
  Type: Initial release
  
• Version 1.1: 2008-04-27
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance