3P42

Structure of GfcC (YmcB), protein encoded by the E. coli group 4 capsule operon

Summary for 3P42

• Entry DOI: 10.2210/pdb3p42/pdb
• Descriptor: Predicted protein, SULFATE ION (3 entities in total)
• Functional Keywords: beta-grasp, unknown function
• Biological source: Escherichia coli O127:H6
• Total number of polymer chains: 4
• Total formula weight: 105352.66

Authors

Saper, M.A.,Sathiyamoorthy, K. (deposition date: 2010-10-05, release date: 2011-04-06, Last modification date: 2024-10-16)

Primary citation

Sathiyamoorthy, K.,Mills, E.,Franzmann, T.M.,Rosenshine, I.,Saper, M.A.
The Crystal Structure of Escherichia coli Group 4 Capsule Protein GfcC Reveals a Domain Organization Resembling That of Wza.
Biochemistry, 50:5465-5476, 2011

PubMed Abstract: We report the 1.9 Å resolution crystal structure of enteropathogenic Escherichia coli GfcC, a periplasmic protein encoded by the gfc operon, which is essential for assembly of group 4 polysaccharide capsule (O-antigen capsule). Presumed gene orthologs of gfcC are present in capsule-encoding regions of at least 29 genera of Gram-negative bacteria. GfcC, a member of the DUF1017 family, is comprised of tandem β-grasp (ubiquitin-like) domains (D2 and D3) and a carboxyl-terminal amphipathic helix, a domain arrangement reminiscent of that of Wza that forms an exit pore for group 1 capsule export. Unlike the membrane-spanning C-terminal helix from Wza, the GfcC C-terminal helix packs against D3. Previously unobserved in a β-grasp domain structure is a 48-residue helical hairpin insert in D2 that binds to D3, constraining its position and sequestering the carboxyl-terminal amphipathic helix. A centrally located and invariant Arg115 not only is essential for proper localization but also forms one of two mostly conserved pockets. Finally, we draw analogies between a GfcC protein fused to an outer membrane β-barrel pore in some species and fusion proteins necessary for secreting biofilm-forming exopolysaccharides.

PubMed: 21449614
DOI: 10.1021/bi101869h

Experimental method

X-RAY DIFFRACTION (1.91 Å)