Amino acid substitutions in the F-specific domain in the stalk of the newcastle disease virus HN protein modulate fusion and interfere with its interaction with the F protein

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Molecular Genetics and Microbiology

Publication Date


Document Type



Life Sciences | Medicine and Health Sciences


The hemagglutinin-neuraminidase (HN) protein of Newcastle disease virus mediates attachment to sialic acid receptors, as well as cleavage of the same moiety. HN also interacts with the other viral glycoprotein, the fusion (F) protein, to promote membrane fusion. The ectodomain of the HN spike consists of a stalk and a terminal globular head. The most conserved part of the stalk consists of two heptad repeats separated by a nonhelical intervening region (residues 89 to 95). Several amino acid substitutions for a completely conserved proline residue in this region not only impair fusion and the HN-F interaction but also decrease neuraminidase activity in the globular domain, suggesting that the substitutions may alter HN structure. Substitutions for L94 also interfere with fusion and the HN-F interaction but have no significant effect on any other HN function. Amino acid substitutions at other positions in the intervening region also modulate only fusion. In all cases, diminished fusion correlates with a decreased ability of the mutated HN protein to interact with F at the cell surface. These findings indicate that the intervening region is critical to the role of HN in the promotion of fusion and may be directly involved in its interaction with the homologous F protein.

DOI of Published Version



J Virol. 2004 Dec;78(23):13053-61. Link to article on publisher's site

Journal/Book/Conference Title

Journal of virology

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Link to article in PubMed

PubMed ID