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

Journal Article · Thu Oct 02 04:00:00 EDT 2014 · J. Virol.

DOI:https://doi.org/10.1128/JVI.06350-11· OSTI ID:1050071

Bose, Sayantan; Welch, Brett D.; Kors, Christopher A.; Yuan, Ping; Jardetzky, Theodore S.; Lamb, Robert A. ^[1]

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1. NWU

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 {angstrom}, 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.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: NIH
• OSTI ID: 1050071
• Journal Information: J. Virol., Journal Name: J. Virol. Journal Issue: (24) ; 12, 2011 Vol. 85; ISSN JOVIAM; ISSN 0022-538X
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
ACTIVATION ENERGY
CRYSTAL STRUCTURE
DISULFIDES
ELECTRON DENSITY
MEMBRANES
MUTAGENESIS
MUTANTS
PROTEINS
RESIDUES
RESOLUTION