Open AccessBiochemical, biophysical and preliminary X‐ray crystallographic analyses of the fusion core of Sendai virus F protein
Author(s) -
Wang Xiaojia,
Xu Yanhui,
Cole David K.,
Lou Zhiyong,
Liu Yiwei,
Rao Zihe,
Wang Ming,
Gao George F.
Publication year - 2004
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
ISSN - 1399-0047
DOI - 10.1107/s0907444904015872
Subject(s) - heptad repeat , sendai virus , coiled coil , helix bundle , crystallography , fusion protein , lipid bilayer fusion , biophysics , protein structure , fusion , linker , helix (gastropod) , conformational change , chemistry , biology , peptide sequence , biochemistry , recombinant dna , ecology , linguistics , philosophy , snail , computer science , gene , operating system , membrane
It is emerging that enveloped viruses may adopt a unique entry/fusion mechanism; in paramyxoviruses, including Sendai virus (SeV), the attachment protein HN (or its homologue H or G) binds a cellular receptor which triggers conformational changes of its fusion protein, F. There are at least three conformations of the F protein in the current fusion model: the pre‐fusion native conformation, the pre‐hairpin intermediate conformation and the post‐fusion coiled‐coil conformation. The fusion mechanism of SeV, a member of the Paramyxoviridae family, has been well established and several structural and functional domains or modules have been proposed from studies of its F protein. However, biochemical and biophysical studies of the heptad‐repeat (HR) regions (HR1 and HR2) have not been systematically carried out. HR1 and HR2 strongly interact with each other to form a stable six‐helix coiled‐coil bundle as the post‐fusion conformation. In this study, a single‐chain HR1–linker–HR2 protein of SeV was prepared in an Escherichia coli expression system and biochemical and biophysical analyses showed it to form a typical six‐helix coiled‐coil bundle; its trigonal crystals diffracted X‐rays to 2.5 Å resolution. The crystal structure will help to reveal the structural requirements of the post‐fusion coiled‐coil conformation of SeV F protein.