4DQ9

Crystal structure of the minor pseudopilin EPSH from the type II secretion system of Vibrio cholerae

Summary for 4DQ9

• Entry DOI: 10.2210/pdb4dq9/pdb
• Related: 2QV8
• Descriptor: General secretion pathway protein H, SODIUM ION, CHLORIDE ION, ... (4 entities in total)
• Functional Keywords: type ii secretion system, pseudopilin, pseudopilus, transport protein
• Biological source: Vibrio cholerae
• Total number of polymer chains: 2
• Total formula weight: 39172.66

Authors

Raghunathan, K.,Vago, F.S.,Grindem, D.,Ball, T.,Wedemeyer, W.J.,Arvidson, D.N. (deposition date: 2012-02-15, release date: 2013-03-13, Last modification date: 2024-02-28)

Primary citation

Raghunathan, K.,Vago, F.S.,Grindem, D.,Ball, T.,Wedemeyer, W.J.,Bagdasarian, M.,Arvidson, D.N.
The 1.59 angstrom resolution structure of the minor pseudopilin EpsH of Vibrio cholerae reveals a long flexible loop.
Biochim.Biophys.Acta, 1844:406-415, 2013

PubMed Abstract: The type II secretion complex exports folded proteins from the periplasm to the extracellular milieu. It is used by the pathogenic bacterium Vibrio cholerae to export several proteins, including its major virulence factor, cholera toxin. The pseudopilus is an essential component of the type II secretion system and likely acts as a piston to push the folded proteins across the outer membrane through the secretin pore. The pseudopilus is composed of the major pseudopilin, EpsG, and four minor pseudopilins, EpsH, EpsI, EpsJ and EpsK. We determined the x-ray crystal structure of the head domain of EpsH at 1.59Å resolution using molecular replacement with the previously reported EpsH structure, 2qv8, as the template. Three additional N-terminal amino acids present in our construct prevent an artifactual conformation of residues 160-166, present in one of the two monomers of the 2qv8 structure. Additional crystal contacts stabilize a long flexible loop comprised of residues 104-135 that is more disordered in the 2qv8 structure but is partially observed in our structure in very different positions for the two EpsH monomers in the asymmetric unit. In one of the conformations the loop is highly extended. Modeling suggests the highly charged loop is capable of contacting EpsG and possibly secreted protein substrates, suggesting a role in specificity of pseudopilus assembly or secretion function.

PubMed: 24316251
DOI: 10.1016/j.bbapap.2013.11.013

Experimental method

X-RAY DIFFRACTION (1.59 Å)