PT  - JOURNAL ARTICLE
AU  - Paschke, Ronja
AU  - Mohr, Swantje
AU  - Lange, Sascha
AU  - Lange, Adam
AU  - Kozuch, Jacek
TI  - In-situ spectroscopic detection of large-scale reorientations of transmembrane α-helices during viroporin channel opening
AID  - 10.1101/2023.06.22.546036
DP  - 2023 Jan 01
TA  - bioRxiv
PG  - 2023.06.22.546036
4099  - http://biorxiv.org/content/early/2023/06/22/2023.06.22.546036.short
4100  - http://biorxiv.org/content/early/2023/06/22/2023.06.22.546036.full
AB  - Viroporins are small ion channels in membranes of enveloped viruses that play key roles during viral life cycles. To use viroporins as drug targets against viral infection requires in-depth mechanistic understanding and, with that, methods that enable investigations under in-situ conditions. Here, we apply surface-enhanced infrared absorption (SEIRA) spectroscopy to Influenza A M2 reconstituted within a solid-supported membrane, to shed light on the mechanics of its viroporin function. M2 is a paradigm of pH-activated proton channels and controls the proton flux into the viral interior during viral infection. We use SEIRA to track the large-scale reorientation of M2’s transmembrane α-helices in-situ during pH-activated channel opening. We quantify this event as a helical tilt from 26° to 40° by correlating the experimental results with solid-state NMR-informed computational spectroscopy. This mechanical motion is impeded upon addition of the inhibitor rimantadine, giving a direct spectroscopic marker to test antiviral activity. The presented approach provides a spectroscopic tool to quantify large-scale structural changes and to track the function and inhibition of the growing number of viroporins from pathogenic viruses in future studies.Competing Interest StatementThe authors have declared no competing interest.