Conformational mapping of a viral fusion peptide in structure-promoting solvents using circular dichroism and electrospray mass spectrometry
✍ Scribed by Alan J. Waring; Patrick W. Mobley; Larry M. Gordon
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 151 KB
- Volume
- 33
- Category
- Article
- ISSN
- 0887-3585
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✦ Synopsis
The N-terminal domain of human immunodeficiency virus (HIV)-1 glycoprotein 41,000 (FP; residues 1-23; NH 2 -AVGIGALFL-GFLGAAGSTMGARS-CONH 2 ) is involved in the fusion and cytolytic processes underlying viralcell infection. Here, we use circular dichroism (CD) spectroscopy, along with electrospray ionization (ESI) mass spectrometry and tandem (MS/MS) mass spectrometry during the course of hydrogen/deuterium exchange, to probe the local conformations of this synthetic peptide in two membrane mimics. Since amino acids that participate in defined secondary structure (i.e., ␣-helix or -sheet) exchange amido hydrogens more slowly than residues in random structures, deuterium exchange was combined with CD spectroscopy to map conformations to specific residues. For FP suspended in the highly structure-promoting solvent hexafluoroisopropanol (HFIP), CD spectra indicated high ␣-helix and disordered structures, whereas ESI and MS/MS mass spectrometry indicated that residues 5-15 were ␣-helical and 16-23 were disordered. For FP suspended in the less structure-promoting solvent trifluoroethanol (TFE), CD spectra showed lower ␣-helix, with ESI and MS/MS mass spectrometry indicating that only residues 9-15 participated in the ␣-helix. These results compare favorably with previous two-dimensional nuclear magnetic resonance studies on the same peptide.