Structural Study of the Relationship between the Rate of Membrane Fusion and the Ability of the Fusion Peptide of Influenza Virus To Perturb Bilayers

Colotto, A.; Epand, Richard M.

doi:10.1021/bi970382u

Cited by 86 publications

(74 citation statements)

References 42 publications

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“…Compared with the FP of the same protein, which converted only a small fraction of the DOPE 31 P spectrum to an isotropic peak (11), the TMD converted most of the intensity to an isotropic peak, indicating that the TMD has stronger curvature-generating ability than the FP. These results counter the prevailing view that viral fusion TMDs are a passive membrane anchor while the FPs are the chief causative agent of bilayer destabilization (36)(37)(38).…”

Section: Discussioncontrasting

confidence: 71%

Viral fusion protein transmembrane domain adopts β-strand structure to facilitate membrane topological changes for virus–cell fusion

Yao

Lee

Waring

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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The C-terminal transmembrane domain (TMD) of viral fusion proteins such as HIV gp41 and influenza hemagglutinin (HA) is traditionally viewed as a passive α-helical anchor of the protein to the virus envelope during its merger with the cell membrane. The conformation, dynamics, and lipid interaction of these fusion protein TMDs have so far eluded high-resolution structure characterization because of their highly hydrophobic nature. Using magicangle-spinning solid-state NMR spectroscopy, we show that the TMD of the parainfluenza virus 5 (PIV5) fusion protein adopts lipid-dependent conformations and interactions with the membrane and water. In phosphatidylcholine (PC) and phosphatidylglycerol (PG) membranes, the TMD is predominantly α-helical, but in phosphatidylethanolamine (PE) membranes, the TMD changes significantly to the β-strand conformation. Measured order parameters indicate that the strand segments are immobilized and thus oligomerized. 31 P NMR spectra and small-angle X-ray scattering (SAXS) data show that this β-strand-rich conformation converts the PE membrane to a bicontinuous cubic phase, which is rich in negative Gaussian curvature that is characteristic of hemifusion intermediates and fusion pores. 1 H-31 P 2D correlation spectra and 2 H spectra show that the PE membrane with or without the TMD is much less hydrated than PC and PG membranes, suggesting that the TMD works with the natural dehydration tendency of PE to facilitate membrane merger. These results suggest a new viral-fusion model in which the TMD actively promotes membrane topological changes during fusion using the β-strand as the fusogenic conformation.solid-state NMR spectroscopy | small-angle X-ray scattering | conformational polymorphism | membrane curvature | peptide-membrane interactions V iral fusion proteins mediate entry of enveloped viruses into cells by merging the viral lipid envelope and the cell membrane. The membrane-interacting subunit of these glycoproteins contains two hydrophobic domains: a fusion peptide (FP) that is usually located at the N terminus and a transmembrane domain (TMD) at the C terminus (1). Together, these domains sandwich a water-soluble ectodomain with a helical segment that trimerizes into a coiled coil. During virus-cell fusion, the trimeric protein, which initially adopts a compact structure, unfolds to an extended intermediate that exposes the FP to the target cell membrane while keeping the TMD in the virus envelope. This extended conformation then folds onto itself to form a trimer of hairpins, in so doing pulling the cell membrane and the virus envelope into close proximity (2, 3). Subsequently, the FP and TMD are hypothesized to deform the two membranes and dehydrate them (4), eventually causing a fusion pore and a fully merged membrane. In the postfusion state, most viral fusion proteins exhibit a six-helixbundle structure in the ectodomain due to the trimer of hairpins (5).This model of virus-cell fusion largely derives from crystal structures of fusion proteins in the pre-and postfusion st...

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Section: Discussioncontrasting

confidence: 71%

Viral fusion protein transmembrane domain adopts β-strand structure to facilitate membrane topological changes for virus–cell fusion

Yao

Lee

Waring

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…lipid mixing (11)(12)(13)(14). Although a lot of information on the correlation of the viral synthetic fusion peptides lytic and fusogenic activity with the peptide secondary structure is available (see e.g.…”

Section: Simian Immunodeficiency Virus (Siv)mentioning

confidence: 99%

Characterization of the Sequence of Interactions of the Fusion Domain of the Simian Immunodeficiency Virus with Membranes

Cladera

Martin

Ruysschaert

et al. 1999

Journal of Biological Chemistry

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The simian immunodeficiency virus fusion peptide constitutes a 12-residue N-terminal segment of the gp32 protein that is involved in the fusion between the viral and cellular membranes, facilitating the penetration of the virus in the host cell. Simian immunodeficiency virus fusion peptide is a hydrophobic peptide that in Me 2 SO forms aggregates that contain ␤-sheet pleated structures. When added to aqueous media the peptide forms large colloidal aggregates. In the presence of lipidic membranes, however, the peptide interacts with the membranes and causes small changes of the membrane electrostatic potential as shown by fluorescein phosphatidylethanolamine fluorescence. Thioflavin T fluorescence and Fourier transformed infrared spectroscopy measurements reveal that the interaction of the peptide with the membrane bilayer results in complete disassembly of the aggregates originating from an Me 2 SO stock solution. Above a lipid/peptide ratio of about 5, the membrane disaggregation and water precipitation processes become dependent on the absolute peptide concentration rather than on the lipid/peptide ratio. A schematic mechanism is proposed, which sheds light on how peptide-peptide interactions can be favored with respect to peptide-lipid interactions at various lipid/peptide ratios. These studies are augmented by the use of the fluorescent dye 1-(3-sulfonatopropyl)-4-[␤[2-(di-n-octylamino)-6-naphthyl]vinyl] pyridinium betaine that shows the interaction of the peptide with the membranes has a clear effect on the magnitude of the so-called dipole potential that arises from dipolar groups located on the lipid molecules and oriented water molecules at the membrane-water interface. It is shown that the variation of the membrane dipole potential affects the extent of the membrane fusion caused by the peptide and implicates the dipolar properties of membranes in their fusion.

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“…Several findings indicate that the fusion peptide inserted into the target membrane would cause the distortion of the bilayer organization necessary for merging (6,30). Hydropathy-at-interface plots elaborated according to the hydrophobicity scale developed by Wimley and White (33,42,45) identify, in addition to the fusion peptide, a second region within the ectodomain of the fusogenic HIV-1 gp41 that shows high tendency to partition into the membrane interface.…”

mentioning

confidence: 99%

Membrane Interface-Interacting Sequences within the Ectodomain of the Human Immunodeficiency Virus Type 1 Envelope Glycoprotein: Putative Role during Viral Fusion

Suárez

Gallaher

Agirre

et al. 2000

J Virol

171

212

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We have identified a region within the ectodomain of the fusogenic human immunodeficiency virus type 1 (HIV-1) gp41, different from the fusion peptide, that interacts strongly with membranes. This conserved sequence, which immediately precedes the transmembrane anchor, is not highly hydrophobic according to the Kyte-Doolittle hydropathy prediction algorithm, yet it shows a high tendency to partition into the membrane interface, as revealed by the Wimley-White interfacial hydrophobicity scale. We have investigated here the membrane effects induced by NH 2 -DKWASLWNWFNITNWLWYIK-CONH 2 (HIV c ), the membrane interfacepartitioning region at the C terminus of the gp41 ectodomain, in comparison to those caused by NH 2 -AVGIGALFLGFLGAAGSTMGARS-CONH 2 (HIV n ), the fusion peptide at the N terminus of the subunit. Both HIV c and HIV n were seen to induce membrane fusion and permeabilization, although lower doses of HIV c were required for comparable effects to be detected. Experiments in which equimolar mixtures of HIV c and HIV n were used indicated that both peptides may act in a cooperative way. Peptide-membrane and peptide-peptide interactions underlying those effects were further confirmed by analyzing the changes in fluorescence of peptide Trp residues. Replacement of the first three Trp residues by Ala, known to render a defective gp41 phenotype unable to mediate both cell-cell fusion and virus entry, also abrogated the HIV c ability to induce membrane fusion or form complexes with HIV n but not its ability to associate with vesicles. Hydropathy analysis indicated that the presence of two membrane-partitioning stretches separated by a collapsible intervening sequence is a common structural motif among other viral envelope proteins. Moreover, sequences with membrane surfaceresiding residues preceding the transmembrane anchor appeared to be a common feature in viral fusion proteins of several virus families. According to our experimental results, such a feature might be related to their fusogenic function.

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Structural Study of the Relationship between the Rate of Membrane Fusion and the Ability of the Fusion Peptide of Influenza Virus To Perturb Bilayers

Cited by 86 publications

References 42 publications

Viral fusion protein transmembrane domain adopts β-strand structure to facilitate membrane topological changes for virus–cell fusion

Viral fusion protein transmembrane domain adopts β-strand structure to facilitate membrane topological changes for virus–cell fusion

Characterization of the Sequence of Interactions of the Fusion Domain of the Simian Immunodeficiency Virus with Membranes

Membrane Interface-Interacting Sequences within the Ectodomain of the Human Immunodeficiency Virus Type 1 Envelope Glycoprotein: Putative Role during Viral Fusion

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