Dataset Information

Amantadine-induced conformational and dynamical changes of the influenza M2 transmembrane proton channel.

ABSTRACT: The M2 protein of influenza A virus forms a transmembrane proton channel important for viral infection and replication. Amantadine blocks this channel, thus inhibiting viral replication. Elucidating the high-resolution structure of the M2 protein and its change upon amantadine binding is crucial for designing antiviral drugs to combat the growing resistance of influenza A viruses against amantadine. We used magic-angle-spinning solid-state NMR to determine the conformation and dynamics of the transmembrane domain of the protein M2TMP in the apo- and amantadine-bound states in lipid bilayers. (13)C chemical shifts and torsion angles of the protein in 1,2-dilauroyl-sn-glycero-3-phosphatidylcholine (DLPC) bilayers indicate that M2TMP is alpha-helical in both states, but the average conformation differs subtly, especially at the G34-I35 linkage and V27 side chain. In the liquid-crystalline membrane, the complexed M2TMP shows dramatically narrower lines than the apo peptide. Analysis of the homogeneous and inhomogeneous line widths indicates that the apo-M2TMP undergoes significant microsecond-time scale motion, and amantadine binding alters the motional rates, causing line-narrowing. Amantadine also reduces the conformational heterogeneity of specific residues, including the G34/I35 pair and several side chains. Finally, amantadine causes the helical segment N-terminal to G34 to increase its tilt angle by 3 degrees , and the G34-I35 torsion angles cause a kink of 5 degrees in the amantadine-bound helix. These data indicate that amantadine affects the M2 proton channel mainly by changing the distribution and exchange rates among multiple low-energy conformations and only subtly alters the average conformation and orientation. Amantadine-resistant mutations thus may arise from binding-incompetent changes in the conformational equilibrium.

SUBMITTER: Cady SD

PROVIDER: S-EPMC2234170 | biostudies-literature | 2008 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Amantadine-induced conformational and dynamical changes of the influenza M2 transmembrane proton channel.

Cady Sarah D SD Hong Mei M

Proceedings of the National Academy of Sciences of the United States of America 20080129 5

The M2 protein of influenza A virus forms a transmembrane proton channel important for viral infection and replication. Amantadine blocks this channel, thus inhibiting viral replication. Elucidating the high-resolution structure of the M2 protein and its change upon amantadine binding is crucial for designing antiviral drugs to combat the growing resistance of influenza A viruses against amantadine. We used magic-angle-spinning solid-state NMR to determine the conformation and dynamics of the tr ...[more]

PMID: 18230730

Similar Datasets

Project description:The M2 protein from influenza A plays important roles in its viral cycle. It contains a single transmembrane helix, which oligomerizes into a homotetrameric proton channel that conducts in the low-pH environment of the host-cell endosome and Golgi apparatus, leading to virion uncoating at an early stage of infection. We studied conformational rearrangements that occur in the M2 core transmembrane domain residing on the lipid bilayer, flanked by juxtamembrane residues (M2TMD21-49 fragment), upon its interaction with amantadine drug at pH 5.5 when M2 is conductive. We also tested the role of specific mutation and lipid chain length. Electron spin resonance (ESR) spectroscopy and electron microscopy were applied to M2TMD21-49, labeled at the residue L46C with either nitroxide spin-label or Nanogold® reagent, respectively. Electron microscopy confirmed that M2TMD21-49 reconstituted into DOPC/POPS at 1:10,000 peptide-to-lipid molar ratio (P/L) either with or without amantadine, is an admixture of monomers, dimers, and tetramers, confirming our model based on a dimer intermediate in the assembly of M2TMD21-49. As reported by double electron-electron resonance (DEER), in DOPC/POPS membranes amantadine shifts oligomer equilibrium to favor tetramers, as evidenced by an increase in DEER modulation depth for P/L's ranging from 1:18,000 to 1:160. Furthermore, amantadine binding shortens the inter-spin distances (for nitroxide labels) by 5-8 Å, indicating drug induced channel closure on the C-terminal side. No such effect was observed for the thinner membrane of DLPC/DLPS, emphasizing the role of bilayer thickness. The analysis of continuous wave (cw) ESR spectra of spin-labeled L46C residue provides additional support to a more compact helix bundle in amantadine-bound M2TMD 21-49 through increased motional ordering. In contrast to wild-type M2TMD21-49, the amantadine-bound form does not exhibit noticeable conformational changes in the case of G34A mutation found in certain drug-resistant influenza strains. Thus, the inhibited M2TMD21-49 channel is a stable tetramer with a closed C-terminal exit pore. This work is aimed at contributing to the development of structure-based anti-influenza pharmaceuticals.

Dataset Information

Amantadine-induced conformational and dynamical changes of the influenza M2 transmembrane proton channel.

Publications

Amantadine-induced conformational and dynamical changes of the influenza M2 transmembrane proton channel.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets