PDBsum entry 2poh

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protein Protein-protein interface(s) links
Viral protein PDB id
Protein chains
(+ 0 more) 233 a.a. *
Waters ×886
* Residue conservation analysis
PDB id:
Name: Viral protein
Title: Structure of phage p22 tail needle gp26
Structure: Head completion protein. Chain: a, b, c, d, e, f. Engineered: yes. Mutation: yes
Source: Salmonella phage p22-pbi. Organism_taxid: 200913. Gene: 26. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.
2.10Å     R-factor:   0.167     R-free:   0.232
Authors: A.S.Olia,G.Cingolani
Key ref: A.S.Olia et al. (2007). Structure of phage P22 cell envelope–penetrating needle. Nat Struct Mol Biol, 14, 1221-1226. PubMed id: 18059287
26-Apr-07     Release date:   04-Dec-07    
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Protein chains
P35837  (VG26_BPP22) -  Tail needle protein gp26
233 a.a.
233 a.a.*
Key:    Secondary structure  CATH domain
* PDB and UniProt seqs differ at 2 residue positions (black crosses)

 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     virion   1 term 
  Biological process     ?   2 terms 


Nat Struct Mol Biol 14:1221-1226 (2007)
PubMed id: 18059287  
Structure of phage P22 cell envelope–penetrating needle.
A.S.Olia, S.Casjens, G.Cingolani.
Bacteriophage P22 infects Salmonella enterica by injecting its genetic material through the cell envelope. During infection, a specialized tail needle, gp26, is injected into the host, likely piercing a hole in the host cell envelope. The 2.1-A crystal structure of gp26 reveals a 240-A elongated protein fiber formed by two trimeric coiled-coil domains interrupted by a triple beta-helix. The N terminus of gp26 plugs the portal protein channel, retaining the genetic material inside the virion. The C-terminal tip of the fiber exposes beta-hairpins with hydrophobic tips similar to those seen in class II fusion peptides. The alpha-helical core connecting these two functionally polarized tips presents four trimerization octads with consensus sequence IXXLXXXV. The slender conformation of the gp26 fiber minimizes the surface exposed to solvent, which is consistent with the idea that gp26 traverses the cell envelope lipid bilayers.