6u02
CryoEM-derived model of NA-63 Fab in complex with N9 Shanghai2
Structural highlights
FunctionS5MF06_9INFA Catalyzes the removal of terminal sialic acid residues from viral and cellular glycoconjugates. Cleaves off the terminal sialic acids on the glycosylated HA during virus budding to facilitate virus release. Additionally helps virus spread through the circulation by further removing sialic acids from the cell surface. These cleavages prevent self-aggregation and ensure the efficient spread of the progeny virus from cell to cell. Otherwise, infection would be limited to one round of replication. Described as a receptor-destroying enzyme because it cleaves a terminal sialic acid from the cellular receptors. May facilitate viral invasion of the upper airways by cleaving the sialic acid moities on the mucin of the airway epithelial cells. Likely to plays a role in the budding process through its association with lipid rafts during intracellular transport. May additionally display a raft-association independent effect on budding. Plays a role in the determination of host range restriction on replication and virulence. Sialidase activity in late endosome/lysosome traffic seems to enhance virus replication.[HAMAP-Rule:MF_04071][SAAS:SAAS00844152] Publication Abstract from PubMedInfluenza virus neuraminidase (NA) is a major target for small-molecule antiviral drugs. Antibodies targeting the NA surface antigen could also inhibit virus entry and egress to provide host protection. However, our understanding of the nature and range of target epitopes is limited because of a lack of human antibody structures with influenza neuraminidase. Here, we describe crystal and cryogenic electron microscopy (cryo-EM) structures of NAs from human-infecting avian H7N9 viruses in complex with five human anti-N9 antibodies, systematically defining several antigenic sites and antibody epitope footprints. These antibodies either fully or partially block the NA active site or bind to epitopes distant from the active site while still showing neuraminidase inhibition. The inhibition of antibodies to NAs was further analyzed by glycan array and solution-based NA activity assays. Together, these structural studies provide insights into protection by anti-NA antibodies and templates for the development of NA-based influenza virus vaccines and therapeutics. Structural Basis of Protection against H7N9 Influenza Virus by Human Anti-N9 Neuraminidase Antibodies.,Zhu X, Turner HL, Lang S, McBride R, Bangaru S, Gilchuk IM, Yu W, Paulson JC, Crowe JE Jr, Ward AB, Wilson IA Cell Host Microbe. 2019 Oct 24. pii: S1931-3128(19)30526-8. doi:, 10.1016/j.chom.2019.10.002. PMID:31757767[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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