3GUD image
Entry Detail
PDB ID:
3GUD
Keywords:
Title:
Crystal structure of a novel intramolecular chaperon
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2009-03-29
Release Date:
2010-02-02
Method Details:
Experimental Method:
Resolution:
2.20 Å
R-Value Free:
0.23
R-Value Work:
0.19
R-Value Observed:
0.19
Space Group:
P 3
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Neck appendage protein
Chain IDs:A, B
Chain Length:129
Number of Molecules:2
Biological Source:Bacillus phage GA-1
Primary Citation
Crystal structure of an intramolecular chaperone mediating triple-beta-helix folding.
Nat.Struct.Mol.Biol. 17 210 215 (2010)
PMID: 20118935 DOI: 10.1038/nsmb.1746

Abstact

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.

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