Receptor binding studies disclose a novel class of high-affinity inhibitors of the Escherichia coli FimH adhesin

Authors

  • Julie Bouckaert,

    1. Laboratorium voor Ultrastructuur, Vrije Universiteit Brussel (VUB) and Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Building E, Pleinlaan 2, 1050 Brussels, Belgium.
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  • Jenny Berglund,

    1. Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala Biomedical Center, PO Box 590, SE-751 24 Uppsala, Sweden.
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  • Mark Schembri,

    1. School of Molecular and Microbial Sciences, University of Queensland, Brisbane QLD 4072, Australia.
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  • Erwin De Genst,

    1. Laboratorium voor Ultrastructuur, Vrije Universiteit Brussel (VUB) and Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Building E, Pleinlaan 2, 1050 Brussels, Belgium.
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  • Lieve Cools,

    1. Laboratorium voor Ultrastructuur, Vrije Universiteit Brussel (VUB) and Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Building E, Pleinlaan 2, 1050 Brussels, Belgium.
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  • Manfred Wuhrer,

    1. Biomolecular Mass Spectrometry Unit, Department of Parasitology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands.
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  • Chia-Suei Hung,

    1. Department of Molecular Microbiology, Box 8230, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA.
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  • Jerome Pinkner,

    1. Department of Molecular Microbiology, Box 8230, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA.
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  • Rikard Slättegård,

    1. Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
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  • Anton Zavialov,

    1. Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala Biomedical Center, PO Box 590, SE-751 24 Uppsala, Sweden.
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  • Devapriya Choudhury,

    1. Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala Biomedical Center, PO Box 590, SE-751 24 Uppsala, Sweden.
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  • Solomon Langermann,

    1. MedImmune, 35 W. Watkins Mill Road, Gaithersburg, MD 20878, USA.
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  • Scott J. Hultgren,

    1. Department of Molecular Microbiology, Box 8230, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA.
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  • Lode Wyns,

    1. Laboratorium voor Ultrastructuur, Vrije Universiteit Brussel (VUB) and Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Building E, Pleinlaan 2, 1050 Brussels, Belgium.
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  • Per Klemm,

    1. Microbial Adhesion Group, Section for Molecular Microbiology, Technical University of Denmark, BioCentrum-DTU, Building 301, DK-2800 Lyngby, Denmark.
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  • Stefan Oscarson,

    1. Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
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  • Stefan D. Knight,

    Corresponding author
    1. Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala Biomedical Center, PO Box 590, SE-751 24 Uppsala, Sweden.
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  • Henri De Greve

    Corresponding author
    1. Laboratorium voor Ultrastructuur, Vrije Universiteit Brussel (VUB) and Vlaams Interuniversitair Instituut voor Biotechnologie (VIB), Building E, Pleinlaan 2, 1050 Brussels, Belgium.
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  • Present addresses: Centre for Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India; PharmAthene, Inc., 175 Admiral Cochrane Drive, Annapolis, MD 21401, USA. §Both authors contributed equally to this work.

E-mail hdegreve@vub.ac.be; Tel. (+32) 2629 18 44; Fax (+32) 26 29 19 63;

E-mail stefan@xray.bmc.uu.se; Tel. (+46) 18 471 45 54; Fax (+46) 18 53 69 71.

Summary

Mannose-binding type 1 pili are important virulence factors for the establishment of Escherichia coli urinary tract infections (UTIs). These infections are initiated by adhesion of uropathogenic E. coli to uroplakin receptors in the uroepithelium via the FimH adhesin located at the tips of type 1 pili. Blocking of bacterial adhesion is able to prevent infection. Here, we provide for the first time binding data of the molecular events underlying type 1 fimbrial adherence, by crystallographic analyses of the FimH receptor binding domains from a uropathogenic and a K-12 strain, and affinity measurements with mannose, common mono- and disaccharides, and a series of alkyl and aryl mannosides. Our results illustrate that the lectin domain of the FimH adhesin is a stable and functional entity and that an exogenous butyl α- d-mannoside, bound in  the  crystal  structures,  exhibits  a  significantly better affinity for FimH (Kd = 0.15 µM) than mannose (Kd = 2.3 µM). Exploration of the binding affinities of α- d-mannosides with longer alkyl tails revealed affinities up to 5 nM. Aryl mannosides and fructose can also bind with high affinities to the FimH lectin domain, with a 100-fold improvement and 15-fold reduction in affinity, respectively, compared with mannose. Taken together, these relative FimH affinities correlate exceptionally well with the relative concentrations of the same glycans needed for the inhibition of adherence of type 1 piliated E. coli. We foresee that our findings will spark new ideas and initiatives for the development of UTI vaccines and anti-adhesive drugs to prevent anticipated and recurrent UTIs.

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