Related Experiment Videos
Low pH-induced conformational changes in vesicular stomatitis virus glycoprotein involve dramatic structure
F A Carneiro1, A S Ferradosa, A T Da Poian
1Departamento de Bioquimica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, 21941-590 Rio de Janeiro, Brazil.
The Journal of Biological Chemistry
|October 12, 2000
Summary
Vesicular stomatitis virus G protein mediates membrane fusion at acidic pH. Acidification induces structural changes, exposing hydrophobic regions and altering secondary structure for target membrane interaction.
Area of Science:
- Virology
- Structural Biology
- Biochemistry
Background:
- Membrane fusion is crucial for enveloped virus entry into host cells.
- Vesicular stomatitis virus (VSV) entry relies on its G protein mediating fusion at acidic pH.
Purpose of the Study:
- To investigate the structural transitions of VSV G protein induced by acidic pH.
- To understand the molecular mechanisms underlying VSV-mediated membrane fusion.
Main Methods:
- Purification of VSV G protein using nonionic detergent.
- Fusion assays with phospholipid vesicles and Vero cells.
- Intrinsic fluorescence and bis-ANS binding assays to monitor environmental changes.
- Circular dichroism spectroscopy to analyze secondary structure changes.
Main Results:
- Purified G protein mediates fusion at pH 6.0.
- Acidification alters the environment of Tryptophan residues.
- Hydrophobic regions of G protein become exposed at pH 6.2.
- G protein undergoes aggregation at pH 6.0 in the absence of lipids, but interacts with lipids in their presence.
- Significant decrease in alpha-helix content observed near pH 6.0, indicating secondary structure reorganization.
Conclusions:
- VSV G protein undergoes significant structural rearrangements at acidic pH.
- These conformational changes are essential for mediating membrane fusion.
- The G protein adopts a fusion-competent state upon acidification.