Parainfluenza virus 5 (PIV5) is an enveloped, single-stranded, negative-sense RNA virus of the Paramyxoviridae family. PIV5 fusion and entry are mediated by the coordinated action of the receptor-binding protein, hemagglutinin-neuraminidase (HN), and the fusion protein (F). Upon triggering by HN, F undergoes an irreversible ATP- and pH-independent conformational change, going down an energy gra...

During World War I there was much lamentation over the "defects of the draft," and the word "shocking" was in frequent use with reference to the condition of a large proportion of men of military age. When, more recently, it became necessary again for society to interpose a shield of human lives between itself and disaster, its cerebral cells once more became agitated over the report that its y...

Deviations from linearity in the dependence of logarithm protein unfolding rates, log ku(f), as a function mechanical force, f, measurable single molecule experiments, can arise for many reasons. In particular, upward curvature ku(f) f implies that underlying energy landscape must be multidimensional with possibility ensues by parallel pathways. Here, simulations using SOP-SC model wild type β-...

Cell entry by paramyxoviruses requires fusion between viral and cellular membranes. Paramyxovirus infection also gives rise to the formation of multinuclear, fused cells (syncytia). Both types of fusion are mediated by the viral fusion (F) protein, which requires proteolytic processing at a basic cleavage site in order to be active for fusion. In common with most paramyxoviruses, fusion mediate...

While the molecular basis of fusion (F) protein refolding during membrane fusion has been studied extensively in vitro, little is known about the biological significance of membrane fusion activity in parainfluenza virus replication and pathogenesis in vivo. Two recombinant Sendai viruses, F-L179V and F-K180Q, were generated that contain F protein mutations in the heptad repeat A region of the ...

It has been shown that the L289A-mutated Newcastle disease virus (NDV) fusion (F) protein gains the ability to promote fusion of Cos-7 cells independent of the viral hemagglutinin-neuraminidase (HN) protein and exhibits a 50% enhancement in HN-dependent fusion over wild-type (wt) F protein. Here, we show that HN-independent fusion by L289A-F is not exhibited in BHK cells or in several other cel...

A mini-F-coded protein, named F2 protein, binds specifically to mini-F DNA. This protein has a molecular weight of 37,000 and is coded by the A2 segment of the mini-F genome (47.3 to 49.4 kilobases on the F coordinate map). The binding site is located also in the A2 segment of mini-F. This binding site is lost by spontaneous deletion when the A2 segment alone, but not A2 together with its neigh...