Download MendeleyAtomic structures of closed and open influenza B M2 proton channel reveal the conduction mechanism.
Mandala, V.S., Loftis, A.R., Shcherbakov, A.A., Pentelute, B.L., Hong, M.(2020) Nat Struct Mol Biol 27: 160-167
- PubMed: 32015551
- DOI: https://doi.org/10.1038/s41594-019-0371-2
- Primary Citation of Related Structures:
6PVR, 6PVT - 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.
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
Organizational Affiliation:
