5b2c
Crystal structure of Mumps virus hemagglutinin-neuraminidase
Structural highlights
FunctionPublication Abstract from PubMedMumps virus (MuV) remains an important pathogen worldwide, causing epidemic parotitis, orchitis, meningitis, and encephalitis. Here we show that MuV preferentially uses a trisaccharide containing alpha2,3-linked sialic acid in unbranched sugar chains as a receptor. Crystal structures of the MuV attachment protein hemagglutinin-neuraminidase (MuV-HN) alone and in complex with the alpha2,3-sialylated trisaccharide revealed that in addition to the interaction between the MuV-HN active site residues and sialic acid, other residues, including an aromatic residue, stabilize the third sugar of the trisaccharide. The importance of the aromatic residue and the third sugar in the MuV-HN-receptor interaction was confirmed by computational energy calculations, isothermal titration calorimetry studies, and glycan-binding assays. Furthermore, MuV-HN was found to bind more efficiently to unbranched alpha2,3-sialylated sugar chains compared with branched ones. Importantly, the strategically located aromatic residue is conserved among the HN proteins of sialic acid-using paramyxoviruses, and alanine substitution compromised their ability to support cell-cell fusion. These results suggest that not only the terminal sialic acid but also the adjacent sugar moiety contribute to receptor function for mumps and these paramyxoviruses. The distribution of structurally different sialylated glycans in tissues and organs may explain in part MuV's distinct tropism to glandular tissues and the central nervous system. In the crystal structure, the epitopes for neutralizing antibodies are located around the alpha-helices of MuV-HN that are not well conserved in amino acid sequences among different genotypes of MuV. This may explain the fact that MuV reinfection sometimes occurs. Trisaccharide containing alpha2,3-linked sialic acid is a receptor for mumps virus.,Kubota M, Takeuchi K, Watanabe S, Ohno S, Matsuoka R, Kohda D, Nakakita SI, Hiramatsu H, Suzuki Y, Nakayama T, Terada T, Shimizu K, Shimizu N, Shiroishi M, Yanagi Y, Hashiguchi T Proc Natl Acad Sci U S A. 2016 Oct 11;113(41):11579-11584. Epub 2016 Sep 26. PMID:27671656[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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