PDBsum entry 3tsi

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Top Page protein Protein-protein interface(s) links
Viral protein PDB id
Protein chains
50 a.a.
48 a.a.
51 a.a.
Waters ×11

References listed in PDB file
Key reference
Title Structure and mutagenesis of the parainfluenza virus 5 hemagglutinin-Neuraminidase stalk domain reveals a four-Helix bundle and the role of the stalk in fusion promotion.
Authors S.Bose, B.D.Welch, C.A.Kors, P.Yuan, T.S.Jardetzky, R.A.Lamb.
Ref. J Virol, 2011, 85, 12855-12866. [DOI no: 10.1128/JVI.06350-11]
PubMed id 21994464
Paramyxovirus entry into cells requires the fusion protein (F) and a receptor binding protein (hemagglutinin-neuraminidase [HN], H, or G). The multifunctional HN protein of some paramyxoviruses, besides functioning as the receptor (sialic acid) binding protein (hemagglutinin activity) and the receptor-destroying protein (neuraminidase activity), enhances F activity, presumably by lowering the activation energy required for F to mediate fusion of viral and cellular membranes. Before or upon receptor binding by the HN globular head, F is believed to interact with the HN stalk. Unfortunately, until recently none of the receptor binding protein crystal structures have shown electron density for the stalk domain. Parainfluenza virus 5 (PIV5) HN exists as a noncovalent dimer-of-dimers on the surface of cells, linked by a single disulfide bond in the stalk. Here we present the crystal structure of the PIV5-HN stalk domain at a resolution of 2.65 Å, revealing a four-helix bundle (4HB) with an upper (N-terminal) straight region and a lower (C-terminal) supercoiled part. The hydrophobic core residues are a mix of an 11-mer repeat and a 3- to 4-heptad repeat. To functionally characterize the role of the HN stalk in F interactions and fusion, we designed mutants along the PIV5-HN stalk that are N-glycosylated to physically disrupt F-HN interactions. By extensive study of receptor binding, neuraminidase activity, oligomerization, and fusion-promoting functions of the mutant proteins, we found a correlation between the position of the N-glycosylation mutants on the stalk structure and their neuraminidase activities as well as their abilities to promote fusion.
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