PDBsum entry 2os7

Go to PDB code: 
protein Protein-protein interface(s) links
Chaperone PDB id
Protein chains
206 a.a. *
196 a.a. *
* Residue conservation analysis
PDB id:
Name: Chaperone
Title: Caf1m periplasmic chaperone tetramer
Structure: Chaperone protein caf1m. Chain: a, b, c, d, e, f. Synonym: capsule protein fraction 1. Engineered: yes
Source: Yersinia pestis. Organism_taxid: 632. Gene: caf1m. Expressed in: escherichia coli. Expression_system_taxid: 562.
2.90Å     R-factor:   0.252     R-free:   0.298
Authors: S.D.Knight,A.Z.Zavialov
Key ref: A.V.Zavialov and S.D.Knight (2007). A novel self-capping mechanism controls aggregation of periplasmic chaperone Caf1M. Mol Microbiol, 64, 153-164. PubMed id: 17376079
05-Feb-07     Release date:   17-Apr-07    
Go to PROCHECK summary

Protein chains
Pfam   ArchSchema ?
P26926  (CAF1M_YERPE) -  Chaperone protein caf1M
258 a.a.
206 a.a.
Protein chains
Pfam   ArchSchema ?
P26926  (CAF1M_YERPE) -  Chaperone protein caf1M
258 a.a.
196 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     periplasmic space   2 terms 
  Biological process     chaperone-mediated protein folding   3 terms 
  Biochemical function     protein binding     1 term  


Mol Microbiol 64:153-164 (2007)
PubMed id: 17376079  
A novel self-capping mechanism controls aggregation of periplasmic chaperone Caf1M.
A.V.Zavialov, S.D.Knight.
The chaperone Caf1M belongs to a family of ATP-independent periplasmic chaperones that together with outer membrane ushers assemble and secrete filamentous adhesion organelles in Gram-negative pathogens. It assists in folding and transport of Caf1 subunits of the F1 capsular antigen of Yersinia pestis, the microbe causing bubonic plague. In the periplasm, Caf1M prevents subunit aggregation by capping the extensive hydrophobic surface of activated Caf1. We found that subunit-free Caf1M exists predominantly as a tetramer [K(d) = (2-30) x 10(-14) M(3) in the 12-37 degrees C interval]. A 2.9 A resolution crystal structure of the Caf1M tetramer reveals that each of the four molecules contribute its subunit binding sequences (the A(1) and G(1) strands) to form an eight-stranded hetero-sandwich with a well-packed phenylalanine-rich hydrophobic core. Tetramerization protects chaperone molecules against enzymatic proteolysis. Deletions in the subunit binding motifs completely abolish tetramer assembly, suggesting that the hetero-sandwich is the main structural feature holding the tetramer together. Arresting tetramer assembly by a deletion of the N-terminal binding motif, while leaving the major subunit binding motif VGVFVQFAI (G(1) strand) intact, results in accumulation of unspecific aggregates. Deletions in the VGVFVQFAI motif abolish both tetramer assembly and aggregation, consistent with the predicted high beta-aggregation propensity for this motif. These results suggest that the packing of the aggregation-prone subunit binding sequences into the hetero-domain is a novel molecular mechanism preventing unspecific aggregation of the free chaperone.

Literature references that cite this PDB file's key reference

  PubMed id Reference
19390146 I.Van Molle, K.Moonens, L.Buts, A.Garcia-Pino, S.Panjikar, L.Wyns, H.De Greve, and J.Bouckaert (2009).
The F4 fimbrial chaperone FaeE is stable as a monomer that does not require self-capping of its pilin-interactive surfaces.
  Acta Crystallogr D Biol Crystallogr, 65, 411-420.
PDB codes: 3f65 3f6i 3f6l
17576202 A.Zavialov, G.Zav'yalova, T.Korpela, and V.Zav'yalov (2007).
FGL chaperone-assembled fimbrial polyadhesins: anti-immune armament of Gram-negative bacterial pathogens.
  FEMS Microbiol Rev, 31, 478-514.  
The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB codes are shown on the right.