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Abstract 19F NMR spectroscopy is an attractive and growing area of research with broad applications in biochemistry, chemical biology, medicinal chemistry, and materials science. We have explored fast magic angle spinning (MAS)19F solid‐state NMR spectroscopy in assemblies of HIV‐1 capsid protein. Tryptophan residues with fluorine substitution at the 5‐position of the indole ring were used as the reporters. The19F chemical shifts for the five tryptophan residues are distinct, reflecting differences in their local environment. Spin‐diffusion and radio‐frequency‐driven‐recoupling experiments were performed at MAS frequencies of 35 kHz and 40–60 kHz, respectively. Fast MAS frequencies of 40–60 kHz are essential for consistently establishing19F–19F correlations, yielding interatomic distances of the order of 20 Å. Our results demonstrate the potential of fast MAS19F NMR spectroscopy for structural analysis in large biological assemblies.
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Flanking aromatic residue competition influences transmembrane peptide helix dynamics
To address biophysical principles and lipid interactions that underlie the properties of membrane proteins, modifications that vary the neighbors of tryptophan residues in the highly dynamic transmembrane helix of GW4,20ALP23 (acetyl‐GGAW4A(LA)6LAW20AGA‐amide) were examined using deuterium NMR spectroscopy. It was found that L5,19GW4,20ALP23, a sequence isomer of the low to moderately dynamic GW5,19ALP23, remains highly dynamic. By contrast, a removal of W4 to produce F4,5GW20ALP23 restores a low level of dynamic averaging, similar to that of the F4,5GW19ALP23 helix. Interestingly, a high level of dynamic averaging requires the presence of both tryptophan residues W4 and W20, on opposite faces of the helix, and does not depend on whether residue 5 is Leu or Ala. Aspects of helix unwinding and potential oligomerization are discussed with respect to helix dynamic averaging and the locations of particular residues at a phosphocholine membrane interface.
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- Award ID(s):
- 1713242
- PAR ID:
- 10453951
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- FEBS Letters
- Volume:
- 594
- Issue:
- 24
- ISSN:
- 0014-5793
- Page Range / eLocation ID:
- p. 4280-4291
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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