title: Hendra virus fusion protein transmembrane domain contributes to pre-fusion protein stability.
abstract: Enveloped viruses utilize fusion (F) proteins studding the surface of the virus to facilitate membrane fusion with a target cell membrane. Fusion of the viral envelope with a cellular membrane is required for release of viral genomic material, so the virus can ultimately reproduce and spread. To drive fusion, the F protein undergoes an irreversible conformational change, transitioning from a metastable pre-fusion conformation to a more thermodynamically stable post-fusion structure. Understanding the elements that control stability of the pre-fusion state and triggering to the post-fusion conformation is important for understanding F protein function. Mutations in F protein transmembrane (TM) domains implicated the TM domain in the fusion process, but the structural and molecular details in fusion remain unclear. Previously, analytical ultracentrifugation was utilized to demonstrate that isolated TM domains of Hendra virus F protein associate in a monomer-trimer equilibrium (Smith, E. C., Smith, S. E., Carter, J. R., Webb, S. R., Gibson, K. M., Hellman, L. M., Fried, M. G., and Dutch, R. E. (2013)J. Biol. Chem.288, 35726-35735). To determine factors driving this association, 140 paramyxovirus F protein TM domain sequences were analyzed. A heptad repeat of β-branched residues was found, and analysis of the Hendra virus F TM domain revealed a heptad repeat leucine-isoleucine zipper motif (LIZ). Replacement of the LIZ with alanine resulted in dramatically reduced TM-TM association. Mutation of the LIZ in the whole protein resulted in decreased protein stability, including pre-fusion conformation stability. Together, our data suggest that the heptad repeat LIZ contributed to TM-TM association and is important for F protein function and pre-fusion stability.
authors.affiliation: From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536.
authors.forename: Stacy
authors.initials: S
authors.lastname: Webb
authors.affiliation: From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536.
authors.forename: Tamas
authors.initials: T
authors.lastname: Nagy
authors.affiliation: From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536.
authors.forename: Hunter
authors.initials: H
authors.lastname: Moseley
authors.affiliation: From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536.
authors.forename: Michael
authors.initials: M
authors.lastname: Fried
authors.affiliation: From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536 rdutc2@uky.edu.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Dutch
mesh_terms: D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D000818:Animals; D002522:Chlorocebus aethiops; D045404:Hendra Virus / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D000072417:Protein Domains; D013329:Structure-Activity Relationship; D014758:Viral Core Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D014758:Viral Core Proteins
keywords: conformational change; fusion protein; membrane fusion; paramyxovirus; pre-fusion conformation; transmembrane domain; virus