2KQT

Solid-state NMR structure of the M2 transmembrane peptide of the influenza A virus in DMPC lipid bilayers bound to deuterated amantadine

Summary for 2KQT

• Entry DOI: 10.2210/pdb2kqt/pdb
• Related: 1NYJ 2RLF 3BKD 3C9J
• NMR Information: BMRB: 16612
• Descriptor: M2 protein, (3S,5S,7S)-tricyclo[3.3.1.1~3,7~]decan-1-amine (2 entities in total)
• Functional Keywords: influenza, transmembrane, amantadine, redor, transport protein
• Total number of polymer chains: 4
• Total formula weight: 11072.43

Authors

Cady, S.D.,Schmidt-Rohr, K.,Wang, J.,Soto, C.S.,DeGrado, W.F.,Hong, M. (deposition date: 2009-11-18, release date: 2010-02-09, Last modification date: 2024-05-08)

Primary citation

Cady, S.D.,Schmidt-Rohr, K.,Wang, J.,Soto, C.,DeGrado, W.F.,Hong, M.
Structure of the amantadine binding site of influenza M2 proton channels in lipid bilayers
Nature, 463:689-692, 2010

PubMed Abstract: The M2 protein of influenza A virus is a membrane-spanning tetrameric proton channel targeted by the antiviral drugs amantadine and rimantadine. Resistance to these drugs has compromised their effectiveness against many influenza strains, including pandemic H1N1. A recent crystal structure of M2(22-46) showed electron densities attributed to a single amantadine in the amino-terminal half of the pore, indicating a physical occlusion mechanism for inhibition. However, a solution NMR structure of M2(18-60) showed four rimantadines bound to the carboxy-terminal lipid-facing surface of the helices, suggesting an allosteric mechanism. Here we show by solid-state NMR spectroscopy that two amantadine-binding sites exist in M2 in phospholipid bilayers. The high-affinity site, occupied by a single amantadine, is located in the N-terminal channel lumen, surrounded by residues mutated in amantadine-resistant viruses. Quantification of the protein-amantadine distances resulted in a 0.3 A-resolution structure of the high-affinity binding site. The second, low-affinity, site was observed on the C-terminal protein surface, but only when the drug reaches high concentrations in the bilayer. The orientation and dynamics of the drug are distinct in the two sites, as shown by (2)H NMR. These results indicate that amantadine physically occludes the M2 channel, thus paving the way for developing new antiviral drugs against influenza viruses. The study demonstrates the ability of solid-state NMR to elucidate small-molecule interactions with membrane proteins and determine high-resolution structures of their complexes.

PubMed: 20130653
DOI: 10.1038/nature08722

Experimental method

SOLID-STATE NMR