3FXE image
Entry Detail
PDB ID:
3FXE
Title:
Crystal structure of interacting domains of IcmR and IcmQ (seleno-derivative)
Biological Source:
PDB Version:
Deposition Date:
2009-01-20
Release Date:
2009-04-28
Method Details:
Experimental Method:
Resolution:
2.20 Å
R-Value Free:
0.25
R-Value Work:
0.23
R-Value Observed:
0.23
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Protein IcmQ
Chain IDs:A
Chain Length:57
Number of Molecules:1
Biological Source:Legionella pneumophila
Polymer Type:polypeptide(L)
Description:Protein IcmR
Mutations:L84M
Chain IDs:B
Chain Length:73
Number of Molecules:1
Biological Source:Legionella pneumophila subsp. pneumophila str. Philadelphia 1
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
MSE B MET SELENOMETHIONINE
Primary Citation
Structure and Function of Interacting IcmR-IcmQ Domains from a Type IVb Secretion System in Legionella pneumophila.
Structure 17 590 601 (2009)
PMID: 19368892 DOI: 10.1016/j.str.2009.02.011

Abstact

During infection, Legionella pneumophila creates a replication vacuole within eukaryotic cells and this requires a Type IVb secretion system (T4bSS). IcmQ plays a critical role in the translocase and associates with IcmR. In this paper, we show that the N-terminal domain of IcmQ (Qn) mediates self-dimerization, whereas the C-terminal domain with a basic linker promotes membrane association. In addition, the binding of IcmR to IcmQ prevents self-dimerization and also blocks membrane permeabilization. However, IcmR does not completely block membrane binding by IcmQ. We then determined crystal structures of Qn with the interacting region of IcmR. In this complex, each protein forms an alpha-helical hairpin within a parallel four-helix bundle. The amphipathic nature of helices in Qn suggests two possible models for membrane permeabilization by IcmQ. The Rm-Qn structure also suggests how IcmR-like proteins in other L. pneumophila species may interact with their IcmQ partners.

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Primary Citation of related structures