1Y9L: The X-Ray Structure Of An Secretion System Protein

The ability to translocate virulence proteins into host cells through a type III secretion apparatus (TTSS) is a hallmark of several Gram-negative pathogens including Shigella, Salmonella, Yersinia, Pseudomonas, and enteropathogenic Escherichia coli. In common with other types of bacterial secretion apparatus, the assembly of the TTSS complex requires the preceding formation of its integral outer membrane secretin ring component. We have determined at 1.5 A the structure of MxiM28-142, the Shigella pilot protein that is essential for the assembly and membrane association of the Shigella secretin, MxiD. This represents the first atomic structure of a secretin pilot protein from the several bacterial secretion systems containing an orthologous secretin component. A deep hydrophobic cavity is observed in the novel 'cracked barrel' structure of MxiM, providing a specific binding domain for the acyl chains of bacterial lipids, a proposal that is supported by our various lipid/MxiM complex structures. Isothermal titration analysis shows that the C-terminal domain of the secretin, MxiD525-570, hinders lipid binding to MxiM.
PDB ID: 1Y9LDownload
MMDB ID: 32892
PDB Deposition Date: 2004/12/15
Updated in MMDB: 2012/10
Experimental Method:
x-ray diffraction
Resolution: 1.5  Å
Source Organism:
Similar Structures:
Biological Unit for 1Y9L: monomeric; determined by author
Molecular Components in 1Y9L
Label Count Molecule
Protein (1 molecule)
Lipoprotein Mxim(Gene symbol: mxiM)
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB