Force‐induced globule–coil transition in laminin binding protein and its role for viral–cell membrane fusion |
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| Authors: | Boris N. Zaitsev Fabrizio Benedetti Andrey G. Mikhaylov Denis V. Korneev Sergey K. Sekatskii Tanya Karakouz Pavel A. Belavin Nina A. Netesova Elena V. Protopopova Svetlana N. Konovalova Giovanni Dietler Valery B. Loktev |
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| Affiliation: | 1. Department of Molecular Virology for Flaviviruses and Viral Hepatitis, State Research Center for Virology and Biotechnology “Vector”, Koltsovo, Novosibirsk region, Russia;2. Laboratoire de Physique de la Matière Vivante, IPMC, BSP, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland;3. Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland;4. Institute of Cytology and Genetics, Novosibirsk, Russia;5. Novosibirsk State University, Novosibirsk, Russia |
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| Abstract: | The specific interactions of the pairs laminin binding protein (LBP)–purified tick‐borne encephalitis viral surface protein E and certain recombinant fragments of this protein, as well as West Nile viral surface protein E and certain recombinant fragments of that protein, are studied by combined methods of single‐molecule dynamic force spectroscopy (SMDFS), enzyme immunoassay and optical surface waves‐based biosensor measurements. The experiments were performed at neutral pH (7.4) and acid pH (5.3) conditions. The data obtained confirm the role of LBP as a cell receptor for two typical viral species of the Flavivirus genus. A comparison of these data with similar data obtained for another cell receptor of this family, namely human αVβ3 integrin, reveals that both these receptors are very important. Studying the specific interaction between the cell receptors in question and specially prepared monoclonal antibodies against them, we could show that both interaction sites involved in the process of virus–cell interaction remain intact at pH 5.3. At the same time, for these acid conditions characteristic for an endosome during flavivirus–cell membrane fusion, SMDFS data reveal the existence of a force‐induced (effective already for forces as small as 30–70 pN) sharp globule–coil transition for LBP and LBP–fragments of protein E complexes. We argue that this conformational transformation, being an analog of abrupt first‐order phase transition and having similarity with the famous Rayleigh hydrodynamic instability, might be indispensable for the flavivirus–cell membrane fusion process. Copyright © 2014 John Wiley & Sons, Ltd. |
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| Keywords: | flavivirus– cell membrane fusion single‐molecule dynamic force spectroscopy laminin binding protein flavivirus surface protein E force‐induced globule– coil transition |
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