Probing the metastable state of influenza hemagglutinin
| Autor: | Matthew A. Durst, Carolyn N. Kingsley, Benjamin E. Ramirez, Michael Caffrey, Helena L. Palka-Hamblin, Aleksandar Antanasijevic, Arnon Lavie |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Models Molecular Endosome Protein Conformation Protein subunit Trimer Peptide Hemagglutinin Glycoproteins Influenza Virus Crystallography X-Ray Biochemistry Membrane Fusion 03 medical and health sciences Viral entry Influenza Human Humans Amino Acid Sequence Molecular Biology chemistry.chemical_classification 030102 biochemistry & molecular biology Cell Biology Hydrogen-Ion Concentration Virus Internalization Peptide Conformation 030104 developmental biology Hemagglutinins Membrane protein chemistry Mutagenesis Protein Structure and Folding Biophysics Peptides Alpha helix |
| Zdroj: | Journal of Biological Chemistry |
| ISSN: | 1083-351X 0021-9258 |
| DOI: | 10.1074/jbc.m117.815043 |
| Popis: | Viral entry into host cells is mediated by membrane proteins in a metastable state that transition to a more stable state upon a stimulus. For example, in the influenza envelope protein hemagglutinin (HA), the low pH in the endosome triggers a transition from the metastable prefusion conformation to the stable fusion conformation. To identify probes that interfere with HA function, here we screened a library of H7 HA peptides for inhibition of H7 HA-mediated entry. We discovered a peptide, PEP87 (WSYNAELLVAMENQHTI), that inhibited H7 and H5 HA-mediated entry. PEP87 corresponds to a highly conserved helical region of the HA2 subunit of HA that self-interacts in the neutral pH conformation. Mutagenesis experiments indicated that PEP87 binds to its native region in the HA trimer. We also found that PEP87 is unstructured in isolation but tends to form a helix as evidenced by CD and NMR studies. Fluorescence, chemical cross-linking, and saturation transfer difference NMR data suggested that PEP87 binds to the neutral pH conformation of HA and disrupts the HA structure without affecting its oligomerization state. Together, this work provides support for a model in which PEP87 disrupts HA function by displacing native interactions of the neutral pH conformation. Moreover, our observations indicate that the HA prefusion structure (and perhaps the metastable states of other viral entry proteins) is more dynamic with transient motions being larger than generally appreciated. These findings also suggest that the ensemble of prefusion structures presents many potential sites for targeting in therapeutic interventions. |
| Databáze: | OpenAIRE |
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