Quantitative comparison of human parainfluenza virus hemagglutinin-neuraminidase receptor binding and receptor cleavage

Mary M. Tappert, J. Zachary Porterfield, Padmaja Mehta-D'souza, Shelly Gulati, Gillian M. Air

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


The human parainfluenza virus (hPIV) hemagglutinin-neuraminidase (HN) protein binds (H) oligosaccharide receptors that contain N-acetylneuraminic acid (Neu5Ac) and cleaves (N) Neu5Ac from these oligosaccharides. In order to determine if one of HN's two functions is predominant, we measured the affinity of H for its ligands by a solid-phase binding assay with two glycoprotein substrates and by surface plasmon resonance with three monovalent glycans. We compared the dissociation constant (Kd) values from these experiments with previously determined Michaelis-Menten constants (Kms) for the enzyme activity. We found that glycoprotein substrates and monovalent glycans containing Neu5Ac MathematicalPi-Four.-1.H9251 2-3Gal MathematicalPi-Four.-1.H9252 1-4GlcNAc bind HN with Kd values in the 10 to 100 MathematicalPi-Four.-1.H9262 M range. Km values for HN were previously determined to be on the order of 1 mM (M. M. Tappert, D. F. Smith, and G. M. Air, J. Virol. 85:12146-12159, 2011). A Km value greater than the Kd value indicates that cleavage occurs faster than the dissociation of binding and will dominate under N-permissive conditions. We propose, therefore, that HN is a neuraminidase that can hold its substrate long enough to act as a binding protein. The N activity can therefore regulate binding by reducing virus-receptor interactions when the concentration of receptoris high.

Original languageEnglish
Pages (from-to)8962-8970
Number of pages9
JournalJournal of Virology
Issue number16
StatePublished - Aug 2013

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology


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