Kinetics of interaction of HIV fusion protein (gp41) with lipid membranes studied by real-time AFM imaging

Zeng

Biochemical and Biophysical Research Communications

et al. 2011

Soluble CD4 (sCD4), anti-CD4 antibody, and anti-gp120 antibody have long been regarded as entry inhibitors in human immunodeficiency virus (HIV) therapy. However, the interactions between these HIV entry inhibitors and corresponding target molecules are still poorly understood. In this study, atomic force microscopy (AFM) was utilized to investigate the interaction forces among them. We found that the unbinding forces of sCD4-gp120 interaction, CD4 antigen-antibody interaction, and gp120 antigen-antibody interaction were 25.45 ± 20.46 pN, 51.22 ± 34.64 pN, and 89.87 ± 44.63 pN, respectively, which may provide important mechanical information for understanding the effects of viral entry inhibitors on HIV infection. Moreover, we found that the functionalization of an interaction pair on AFM tip or substrate significantly influenced the results, implying that we must perform AFM force measurement and analyze the data with more caution.

Section: Introductionmentioning

confidence: 99%

AFM force measurements of the gp120–sCD4 and gp120 or CD4 antigen–antibody interactions

Zeng

Biochemical and Biophysical Research Communications

et al. 2011

“…This represents an important progress over conventional transmission electron microscopy, as these techniques make it possible to quantify the dynamics of the infectious entry pathway. Commonly used cell-based techniques are complemented with in vitro bioanalytical assays employing model surface-supported cell membranes of chosen composition [4][5][6]. Such studies, focused on, e.g., ensemble-averaged recording of binding to modelsupported lipid bilayers [5] and virus imaging [6], provide basic knowledge about the contribution of individual components to the processes under consideration.…”

mentioning

confidence: 99%

Interaction of Single Viruslike Particles with Vesicles Containing Glycosphingolipids

et al. 2011

Glycosphingolipids are involved in the first steps of virus-cell interaction, where they mediate specific recognition of the host cell membrane. We have employed total-internal-reflection fluorescence microscopy to explore the interaction kinetics between individual unlabeled noroviruslike particles, which are attached to a glycosphingolipid-containing lipid bilayer, and fluorescent vesicles containing different types and concentrations of glycosphingolipids. Under association equilibrium, the vesicle-binding rate is found to be kinetically limited, yielding information on the corresponding activation energy. The dissociation kinetics are logarithmic over a wide range of time. The latter is explained by the vesicle-size-related distribution of the dissociation activation energy. The biological, pharmaceutical, and diagnostic relevance of the study is briefly discussed.Funding Agencies|Swiss National Science Foundation||VINNOVA||Swedish Foundation for Strategic Research||Swedish Research Council|

“…In this context HIV glycoprotein-lipid interactions have been probed 75 with the ability to observe nanometre scale resolution in real time under physiologically relevant conditions. [13][14][15] In this work glycoprotein lipid interactions have been examined in order to better understand the assembly of the HIV envelope. Virion assembly is usually completed under direction 80 of the host cell machinery, however an in vitro approach has the advantage of being able to elucidate the purely physical/chemical interactions of the biomolecular components.…”

Section: Introductionmentioning

confidence: 99%

“…A similar process has driven a strand of research focusing on cyclodextrin-based assemblies, a potential strategy applicable to the gp41-gp120 complex. 17,18 Virosomes are nanoparticles that contain inactive versions or 15 fractions of a virus. They are used to elicit an immune response, generating antibodies against the viral antigen.…”

Section: Introductionmentioning

confidence: 99%

“…Interactions between trans-membrane gp41 and gp120, the spikes protruding from a virion, were examined using supported lipid bilayers. Interactions between the gp120 and membrane-located gp41 resulted in the assembly of unusual molecular wires, one molecule in height 15 and with a zigzag arrangement of gp120 molecules. In this work we have shown that purely physical/chemical interactions have dramatic effects on glycoprotein/lipid assembly and should be considered in the development of virus based technologies such as virosomes.…”

mentioning

confidence: 99%

See 1 more Smart Citation

In vitro assembly of a viral envelope

et al. 2015

Viruses such as influenza and Ebola are enveloped in lipid bilayers annexed from host cells and containing glycoproteins essential for the infection process. At the molecular level little is known about the assembly process in terms of physical interactions between the lipids and glycoproteins. In this paper we assemble HIV glycoproteins in lipid vesicles in order to examine envelope assembly, a process that is usually only executed under control of a host cell. Using atomic force microscopy it was possible to observe fusion of individual envelope like particles, and contrast this with the behaviour of lipid vesicles without envelope glycoproteins. It was found that the inclusion of glycoproteins caused the vesicles to distort and that the subsequent fusion "footprint" with a lipid bilayer was related to the envelopes' unique morphology. This non-spherical morphology suggests that the presence of a viral capsid may be essential for the stability of an enveloped virus. Interactions between trans-membrane gp41 and gp120, the spikes protruding from a virion, were examined using supported lipid bilayers. Interactions between the gp120 and membrane-located gp41 resulted in the assembly of unusual molecular wires, one molecule in height and with a zigzag arrangement of gp120 molecules. In this work we have shown that purely physical/chemical interactions have dramatic effects on glycoprotein/lipid assembly and should be considered in the development of virus based technologies such as virosomes.