Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Structure. 2009 Apr 15;17(4):590-601. doi: 10.1016/j.str.2009.02.011.

Structure and function of interacting IcmR-IcmQ domains from a type IVb secretion system in Legionella pneumophila.

Author information

  • 1Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118-2526, USA.

Abstract

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.

PMID:
19368892
[PubMed - indexed for MEDLINE]
PMCID:
PMC2693034
Free PMC Article

Images from this publication.See all images (8)Free text

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science Icon for PubMed Central
    Loading ...
    Write to the Help Desk