title: A single mutation in the envelope protein modulates flavivirus antigenicity, stability, and pathogenesis.
abstract: The structural flexibility or 'breathing' of the envelope (E) protein of flaviviruses allows virions to sample an ensemble of conformations at equilibrium. The molecular basis and functional consequences of virus conformational dynamics are poorly understood. Here, we identified a single mutation at residue 198 (T198F) of the West Nile virus (WNV) E protein domain I-II hinge that regulates virus breathing. The T198F mutation resulted in a ~70-fold increase in sensitivity to neutralization by a monoclonal antibody targeting a cryptic epitope in the fusion loop. Increased exposure of this otherwise poorly accessible fusion loop epitope was accompanied by reduced virus stability in solution at physiological temperatures. Introduction of a mutation at the analogous residue of dengue virus (DENV), but not Zika virus (ZIKV), E protein also increased accessibility of the cryptic fusion loop epitope and decreased virus stability in solution, suggesting that this residue modulates the structural ensembles sampled by distinct flaviviruses at equilibrium in a context dependent manner. Although the T198F mutation did not substantially impair WNV growth kinetics in vitro, studies in mice revealed attenuation of WNV T198F infection. Overall, our study provides insight into the molecular basis and the in vitro and in vivo consequences of flavivirus breathing.
authors.affiliation: Viral Pathogenesis Section, National Institutes of Health, Bethesda, MD, United States of America.
authors.forename: Leslie
authors.initials: L
authors.lastname: Goo
authors.affiliation: Departments of Medicine, Molecular Microbiology, Pathology & Immunology, and The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO, United States of America.
authors.forename: Laura A
authors.initials: LA
authors.lastname: VanBlargan
authors.affiliation: Viral Pathogenesis Section, National Institutes of Health, Bethesda, MD, United States of America.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Dowd
authors.affiliation: Departments of Medicine, Molecular Microbiology, Pathology & Immunology, and The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO, United States of America.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Diamond
authors.affiliation: Viral Pathogenesis Section, National Institutes of Health, Bethesda, MD, United States of America.
authors.forename: Theodore C
authors.identifier: 0000-0002-3795-4348
authors.initials: TC
authors.lastname: Pierson
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology*; D003715:Dengue / Q000235:genetics / Q000276:immunology; D003716:Dengue Virus / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D009500:Neutralization Tests; D055550:Protein Stability; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*; D014774:Virulence / Q000235:genetics / Q000276:immunology; D014901:West Nile Fever / Q000235:genetics / Q000276:immunology; D014902:West Nile virus / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D000956:Antigens, Viral; D018985:Epitopes, B-Lymphocyte; D014759:Viral Envelope Proteins; C065696:glycoprotein E, Flavivirus