PDBsum entry 3gw6

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protein ligands metals Protein-protein interface(s) links
Chaperone PDB id
Protein chains
(+ 0 more) 256 a.a. *
PEG ×18
TAM ×3
_CL ×6
_BR ×6
Waters ×323
* Residue conservation analysis
PDB id:
Name: Chaperone
Title: Intramolecular chaperone
Structure: Endo-n-acetylneuraminidase. Chain: a, b, e, c, d, f. Fragment: residues 790-1064. Synonym: endo-alpha-sialidase, gp17 protein. Engineered: yes
Source: Enterobacteria phage k1f. Bacteriophage k1f. Organism_taxid: 344021. Gene: sia, 17, 17.0. Expressed in: escherichia coli. Expression_system_taxid: 562
2.60Å     R-factor:   0.211     R-free:   0.255
Authors: E.C.Schulz,A.Dickmanns,R.Ficner
Key ref: E.C.Schulz et al. (2010). Crystal structure of an intramolecular chaperone mediating triple-beta-helix folding. Nat Struct Mol Biol, 17, 210-215. PubMed id: 20118935
31-Mar-09     Release date:   02-Feb-10    
Go to PROCHECK summary

Protein chains
Pfam   ArchSchema ?
Q04830  (ENAN_BPK1F) -  Endo-N-acetylneuraminidase
920 a.a.
256 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 8 residue positions (black crosses)

 Enzyme reactions 
   Enzyme class: E.C.  - Endo-alpha-sialidase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: Endohydrolysis of (2->8)-alpha-sialosyl linkages in oligo- or poly(sialic) acids.


Nat Struct Mol Biol 17:210-215 (2010)
PubMed id: 20118935  
Crystal structure of an intramolecular chaperone mediating triple-beta-helix folding.
E.C.Schulz, A.Dickmanns, H.Urlaub, A.Schmitt, M.Mühlenhoff, K.Stummeyer, D.Schwarzer, R.Gerardy-Schahn, R.Ficner.
Protein folding is often mediated by molecular chaperones. Recently, a novel class of intramolecular chaperones has been identified in tailspike proteins of evolutionarily distant viruses, which require a C-terminal chaperone for correct folding. The highly homologous chaperone domains are interchangeable between pre-proteins and release themselves after protein folding. Here we report the crystal structures of two intramolecular chaperone domains in either the released or the pre-cleaved form, revealing the role of the chaperone domain in the formation of a triple-beta-helix fold. Tentacle-like protrusions enclose the polypeptide chains of the pre-protein during the folding process. After the assembly, a sensory mechanism for correctly folded beta-helices triggers a serine-lysine catalytic dyad to autoproteolytically release the mature protein. Sequence analysis shows a conservation of the intramolecular chaperones in functionally unrelated proteins sharing beta-helices as a common structural motif.

Literature references that cite this PDB file's key reference

  PubMed id Reference
21330133 E.C.Schulz, and R.Ficner (2011).
Knitting and snipping: chaperones in β-helix folding.
  Curr Opin Struct Biol, 21, 232-239.  
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