2MME

Hybrid structure of the Shigella flexneri MxiH Type three secretion system needle

Summary for 2MME

• Entry DOI: 10.2210/pdb2mme/pdb
• EMDB information: 5352
• NMR Information: BMRB: 18651
• Descriptor: MxiH (1 entity in total)
• Functional Keywords: type-three secretion system, filamentous protein, helical assembly, shigella flexneri, protein translocation, hybrid methods, rosetta, protein transport
• Biological source: Shigella flexneri
• Total number of polymer chains: 29
• Total formula weight: 272493.31

Authors

Demers, J.P.,Habenstein, B.,Loquet, A.,Vasa, S.K.,Becker, S.,Baker, D.,Lange, A.,Sgourakis, N.G. (deposition date: 2014-03-14, release date: 2014-10-08, Last modification date: 2024-05-15)

Primary citation

Demers, J.P.,Habenstein, B.,Loquet, A.,Kumar Vasa, S.,Giller, K.,Becker, S.,Baker, D.,Lange, A.,Sgourakis, N.G.
High-resolution structure of the Shigella type-III secretion needle by solid-state NMR and cryo-electron microscopy.
Nat Commun, 5:4976-4976, 2014

PubMed Abstract: We introduce a general hybrid approach for determining the structures of supramolecular assemblies. Cryo-electron microscopy (cryo-EM) data define the overall envelope of the assembly and rigid-body orientation of the subunits while solid-state nuclear magnetic resonance (ssNMR) chemical shifts and distance constraints define the local secondary structure, protein fold and inter-subunit interactions. Finally, Rosetta structure calculations provide a general framework to integrate the different sources of structural information. Combining a 7.7-Å cryo-EM density map and 996 ssNMR distance constraints, the structure of the type-III secretion system needle of Shigella flexneri is determined to a precision of 0.4 Å. The calculated structures are cross-validated using an independent data set of 691 ssNMR constraints and scanning transmission electron microscopy measurements. The hybrid model resolves the conformation of the non-conserved N terminus, which occupies a protrusion in the cryo-EM density, and reveals conserved pore residues forming a continuous pattern of electrostatic interactions, thereby suggesting a mechanism for effector protein translocation.

PubMed: 25264107
DOI: 10.1038/ncomms5976

Experimental method

ELECTRON MICROSCOPY (7.7 Å)
SOLID-STATE NMR (7.7 Å)