University of Indianapolis1, Indianapolis, IN 46227 University of Kentucky2, Biochemistry, Lexington, KY 40536
Biochemistry
TRANSMEMBRANE INTERACTIONS OF PARAMYXOVIRUS FUSION PROTEINS A. Ashbrook, S. Smith†, M. Fried† and R. E. Dutch*†, †Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 S. Limestone, Lexington, KY 40536, rdut2@uky.edu
Paramyxoviruses are a diverse group of negative-sense RNA viruses including well known viruses such as mumps, measles, the more recently discovered Henipaviruses and the human metapneumovirus. Paramyxoviruses contain transmembrane fusion (F) proteins which mediate fusion between viral and host cell membranes. The F protein is initially synthesized and held in the fusogenically inactive, metastable state (F0), which becomes active through cleavage by endogenous proteases. The conversion provides the energy necessary for viral-host membrane fusion in a “spring-loaded” type mechanism. It is hypothesized that interactions between the transmembrane domains help facilitate this conformational change. Analytical ultracentrifugation was used to determine the stoichiometric ratios and equilibrium constant of the oligomerization within the transmembrane domain of the protein. Centrifugation data of the wildtype and G508I mutant of the Hendra virus (HeV) F protein was analyzed using HeteroAnalysis software. Analysis suggests that most of the transmembrane domains trimerize, while a small portion of the transmembrane domains remain in its monomeric form. Furthermore, the fit of the A.U. data to the monomer-trimer model indicates little variation between the wildtype and mutant proteins, suggesting that the inactivity of the mutant must not be a result of any misfolding of the transmembrane domain in the HeV F protein
[Abstract (DOC)]