A helical RGD motif promoting cell adhesion: Crystal structures of the helicobacter pylori type IV secretion system pilus protein CagL

Barden S, Lange S, Tegtmeyer N, Conradi J, Sewald N, Backert S, Niemann HH (2013)

Publication Type: Journal article

Publication year: 2013

Journal

Structure Elsevier (Cell Press)

Book Volume: 21

Pages Range: 1931-1941

Journal Issue: 11

DOI: 10.1016/j.str.2013.08.018

Abstract

RGD tripeptide motifs frequently mediate ligand binding to integrins. The type IV secretion system (T4SS) protein CagL of the gastric pathogen Helicobacter pylori also contains an RGD motif. CagL decorates the T4SS pilus and may function as an adhesin for host cells. Whether CagL binds integrins via its RGD motif is under debate. Here, we present crystal structures of CagL revealing an elongated four-helix bundle that appears evolutionarily unrelated to the proposed VirB5 orthologs. The RGD motif is surface-exposed but located within a long α helix. This is unprecedented as previously characterized integrin-binding RGD motifs are located within extended or flexible loops. Yet, adhesion of gastric epithelial cells to CagL was strictly RGD-dependent. Comparison of seven crystallographically independent molecules reveals substantial structural flexibility. Intramolecular disulfide bonds engineered to reduce CagL flexibility resulted in more stable protein, but unable to support cell adhesion. CagL may thus partly unfold during receptor binding. © 2013 Elsevier Ltd.

Authors with CRIS profile

Nicole Tegtmeyer-Backert Lehrstuhl für Mikrobiologie Steffen Backert Lehrstuhl für Mikrobiologie

Involved external institutions

Universität Bielefeld DE Germany (DE)

How to cite

APA:

Barden, S., Lange, S., Tegtmeyer, N., Conradi, J., Sewald, N., Backert, S., & Niemann, H.H. (2013). A helical RGD motif promoting cell adhesion: Crystal structures of the helicobacter pylori type IV secretion system pilus protein CagL. Structure, 21(11), 1931-1941. https://doi.org/10.1016/j.str.2013.08.018

MLA:

Barden, Stephan, et al. "A helical RGD motif promoting cell adhesion: Crystal structures of the helicobacter pylori type IV secretion system pilus protein CagL." Structure 21.11 (2013): 1931-1941.

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