The receptor-binding domain of influenza virus hemagglutinin produced in Escherichia coli folds into its native, immunogenic structure.
Title | The receptor-binding domain of influenza virus hemagglutinin produced in Escherichia coli folds into its native, immunogenic structure. |
Publication Type | Journal Article |
Year of Publication | 2011 |
Authors | DuBois, Rebecca M., Aguilar-Yañez José Manuel, Mendoza-Ochoa Gonzalo I., Oropeza-Almazán Yuriana, Schultz-Cherry Stacey, Alvarez Mario Moisés, White Stephen W., and Russell Charles J. |
Journal | J Virol |
Volume | 85 |
Issue | 2 |
Pagination | 865-72 |
Date Published | 2011 Jan |
ISSN | 1098-5514 |
Keywords | Animals, Antibodies, Viral, Binding Sites, Crystallography, X-Ray, Dimerization, Escherichia coli, Ferrets, Hemagglutinins, Viral, Humans, Influenza Vaccines, Models, Molecular, Orthomyxoviridae Infections, Protein Folding, Protein Structure, Quaternary, Protein Structure, Tertiary, Recombinant Proteins |
Abstract | The hemagglutinin (HA) surface glycoprotein promotes influenza virus entry and is the key protective antigen in natural immunity and vaccines. The HA protein is a trimeric envelope glycoprotein consisting of a globular receptor-binding domain (HA-RBD) that is inserted into a membrane fusion-mediating stalk domain. Similar to other class I viral fusion proteins, the fusogenic stalk domain spontaneously refolds into its postfusion conformation when expressed in isolation, consistent with this domain being trapped in a metastable conformation. Using X-ray crystallography, we show that the influenza virus HA-RBD refolds spontaneously into its native, immunogenic structure even when expressed in an unglycosylated form in Escherichia coli. In the 2.10-Å structure of the HA-RBD, the receptor-binding pocket is intact and its conformational epitopes are preserved. Recombinant HA-RBD is immunogenic and protective in ferrets, and the protein also binds with specificity to sera from influenza virus-infected humans. Overall, the data provide a structural basis for the rapid production of influenza vaccines in E. coli. From an evolutionary standpoint, the ability of the HA-RBD to refold spontaneously into its native conformation suggests that influenza virus acquired this domain as an insertion into an ancestral membrane-fusion domain. The insertion of independently folding domains into fusogenic stalk domains may be a common feature of class I viral fusion proteins. |
DOI | 10.1128/JVI.01412-10 |
Alternate Journal | J. Virol. |
PubMed ID | 21068239 |
PubMed Central ID | PMC3020035 |
Grant List | CA21765 / CA / NCI NIH HHS / United States HHSN266200700005C / / PHS HHS / United States |