6PVR

Influenza B M2 Proton Channel in the Closed State - SSNMR Structure at pH 7.5

Summary for 6PVR

• Entry DOI: 10.2210/pdb6pvr/pdb
• NMR Information: BMRB: 30645
• Descriptor: BM2 protein (1 entity in total)
• Functional Keywords: proton channel, closed state, four helix bundle, viral protein
• Biological source: Influenza B virus (B/Maryland/1/2001)
• Total number of polymer chains: 4
• Total formula weight: 23812.58

Authors

Mandala, V.S.,Loftis, A.R.,Shcherbakov, A.S.,Pentelute, B.L.,Hong, M. (deposition date: 2019-07-21, release date: 2020-02-05, Last modification date: 2024-05-01)

Primary citation

Mandala, V.S.,Loftis, A.R.,Shcherbakov, A.A.,Pentelute, B.L.,Hong, M.
Atomic structures of closed and open influenza B M2 proton channel reveal the conduction mechanism.
Nat.Struct.Mol.Biol., 27:160-167, 2020

PubMed Abstract: The influenza B M2 (BM2) proton channel is activated by acidic pH to mediate virus uncoating. Unlike influenza A M2 (AM2), which conducts protons with strong inward rectification, BM2 conducts protons both inward and outward. Here we report 1.4- and 1.5-Å solid-state NMR structures of the transmembrane domain of the closed and open BM2 channels in a phospholipid environment. Upon activation, the transmembrane helices increase the tilt angle by 6° and the average pore diameter enlarges by 2.1 Å. BM2 thus undergoes a scissor motion for activation, which differs from the alternating-access motion of AM2. These results indicate that asymmetric proton conduction requires a backbone hinge motion, whereas bidirectional conduction is achieved by a symmetric scissor motion. The proton-selective histidine and gating tryptophan in the open BM2 reorient on the microsecond timescale, similar to AM2, indicating that side chain dynamics are the essential driver of proton shuttling.

PubMed: 32015551
DOI: 10.1038/s41594-019-0371-2

Experimental method

SOLID-STATE NMR