6wxb
From Proteopedia
Cryo-EM Structure of Influenza Hemagglutinin (HA) Trimer Vitrified Using Back-it-up
Structural highlights
Function[HEMA_I68A4] Binds to sialic acid-containing receptors on the cell surface, bringing about the attachment of the virus particle to the cell. This attachment induces virion internalization of about two third of the virus particles through clathrin-dependent endocytosis and about one third through a clathrin- and caveolin-independent pathway. Plays a major role in the determination of host range restriction and virulence. Class I viral fusion protein. Responsible for penetration of the virus into the cell cytoplasm by mediating the fusion of the membrane of the endocytosed virus particle with the endosomal membrane. Low pH in endosomes induces an irreversible conformational change in HA2, releasing the fusion hydrophobic peptide. Several trimers are required to form a competent fusion pore (By similarity). Publication Abstract from PubMedBlotting times for conventional cryoEM specimen preparation complicate time-resolved studies and lead to some specimens adopting preferred orientations or denaturing at the air-water interface. Here, it is shown that solution sprayed onto one side of a holey cryoEM grid can be wicked through the grid by a glass-fiber filter held against the opposite side, often called the `back', of the grid, producing a film suitable for vitrification. This process can be completed in tens of milliseconds. Ultrasonic specimen application and through-grid wicking were combined in a high-speed specimen-preparation device that was named `Back-it-up' or BIU. The high liquid-absorption capacity of the glass fiber compared with self-wicking grids makes the method relatively insensitive to the amount of sample applied. Consequently, through-grid wicking produces large areas of ice that are suitable for cryoEM for both soluble and detergent-solubilized protein complexes. The speed of the device increases the number of views for a specimen that suffers from preferred orientations. Through-grid wicking enables high-speed cryoEM specimen preparation.,Tan YZ, Rubinstein JL Acta Crystallogr D Struct Biol. 2020 Nov 1;76(Pt 11):1092-1103. doi:, 10.1107/S2059798320012474. Epub 2020 Oct 13. PMID:33135680[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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