3FCG

Crystal Structure Analysis of the Middle Domain of the Caf1A Usher


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.85 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.264 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Caf1A usher possesses a Caf1 subunit-like domain that is crucial for Caf1 fibre secretion

Yu, X.Visweswaran, G.R.Duck, Z.Marupakula, S.MacIntyre, S.Knight, S.D.Zavialov, A.V.

(2009) Biochem.J. 418: 541-551

  • DOI: 10.1042/BJ20080992

  • PubMed Abstract: 
  • The chaperone/usher pathway controls assembly of fibres of adhesive organelles of Gram-negative bacteria. The final steps of fibre assembly and fibre translocation to the cell surface are co-ordinated by the outer membrane proteins, ushers. Ushers co ...

    The chaperone/usher pathway controls assembly of fibres of adhesive organelles of Gram-negative bacteria. The final steps of fibre assembly and fibre translocation to the cell surface are co-ordinated by the outer membrane proteins, ushers. Ushers consist of several soluble periplasmic domains and a single transmembrane beta-barrel. Here we report isolation and structural/functional characterization of a novel middle domain of the Caf1A usher from Yersinia pestis. The isolated UMD (usher middle domain) is a highly soluble monomeric protein capable of autonomous folding. A 2.8 A (1 A=0.1 nm) resolution crystal structure of UMD revealed that this domain has an immunoglobulin-like fold similar to that of donor-strand-complemented Caf1 fibre subunit. Moreover, these proteins displayed significant structural similarity. Although UMD is in the middle of the predicted amphipathic beta-barrel of Caf1A, the usher still assembled in the membrane in the absence of this domain. UMD did not bind Caf1M-Caf1 complexes, but its presence was shown to be essential for Caf1 fibre secretion. The study suggests that UMD may play the role of a subunit-substituting protein (dummy subunit), plugging or priming secretion through the channel in the Caf1A usher. Comparison of isolated UMD with the recent structure of the corresponding domain of PapC usher revealed high similarity of the core structures, suggesting a universal structural adaptation of FGL (F(1)G(1) long) and FGS (F(1)G(1) short) chaperone/usher pathways for the secretion of different types of fibres. The functional role of two topologically different states of this plug domain suggested by structural and biochemical results is discussed.


    Organizational Affiliation

    Department of Molecular Biology, Uppsala Biomedical Centre, Swedish University of Agricultural Sciences, Uppsala, Sweden.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
F1 capsule-anchoring protein
A, B
90Yersinia pestisMutation(s): 0 
Gene Names: caf1A
Find proteins for P26949 (Yersinia pestis)
Go to UniProtKB:  P26949
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CL
Query on CL

Download SDF File 
Download CCD File 
A
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.85 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.264 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 29.985α = 90.00
b = 111.966β = 90.00
c = 115.141γ = 90.00
Software Package:
Software NamePurpose
DNAdata collection
MOSFLMdata reduction
SCALAdata scaling
REFMACrefinement
SOLVEphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-12-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance