The His-Gly motif of acid-sensing ion channels resides in a reentrant ‘loop’ implicated in gating and ion selectivity
- Vollum Institute, Oregon Health & Science University, United States
- Howard Hughes Medical Institute, Oregon Health & Science University, United States
Figures
Figure 1 with 5 supplements
Structures of cASIC1-SMA.
(a-b) Cryo-EM maps of cASIC1-SMA at pH 7.0 (a) and pH 8.0 (b). (c) Cartoon diagram of cASIC1 with single subunit shown colored by domain. (d-e) Pore profiles for cASIC1-SMA in a desensitized (d) and …
Figure 1—figure supplement 1
Purification of cASIC1-SMA.
(a-b) SDS-PAGE (a) and FSEC (b) analysis of SMA-solubilized EGFP-cASIC1 particles after size-exclusion chromatography. (c) Negative stain transmission electron microscopy of SMA-solubilized …
Figure 1—figure supplement 2
Cryo-EM of cASIC1-SMA at pH 7.0.
(a-b) Representative micrograph (a) and 2D classes (b) of cASIC1-SMA at pH 7.0. (c–e) Local resolution estimation (c) angular distribution (d) and gold standard FSC resolution estimation (e) from …
Figure 1—figure supplement 3
Cryo-EM data processing for cASIC1-SMA at pH 7.0.
Data processing strategy for cASIC1-SMA pH 7.0 dataset.
Figure 1—figure supplement 4
Cryo-EM of cASIC1-SMA at pH 8.0.
(a-b) Representative micrograph (a) and 2D classes (b) of cASIC1-SMA at pH 8.0. (c–e) Local resolution estimation (c) angular distribution (d) and gold standard FSC resolution estimation (e) from …
Figure 1—figure supplement 5
Cryo-EM data processing for cASIC1-SMA at pH 8.0.
Data processing strategy for cASIC1-SMA pH 8.0 dataset.
Figure 2 with 1 supplement
Cryo-EM density and structure of the reentrant, pre-TM1 domain.
(a-b) Cryo-EM density corresponding to amino terminal residues of cASIC1-SMA at pH 7.0 (a) and pH 8.0 (b). (c–d) Side (c) and top-down (d) views of the TMD from cASIC1-SMA in a desensitized state at …
Figure 2—figure supplement 1
Polar contacts at the reentrant loop.
(a) Polar interactions between the reentrant loop and neighboring residues. (b) Surface representation of lower TMD showing interfaces between the reentrant loop residues and TM1 and TM2b helices.
Figure 3
The HG motif resides at a subunit interface ‘below’ the GAS belt.
(a) Sequence alignment of selected ASIC1, ASIC3 and ENaC channels covering the pre-TM1 and TM2 domains with GAS domain and HG motif residues highlighted in pink and light blue, respectively, and …
Figure 4
The reentrant loop forms the lower ion permeation pathway.
(a) Overview of pore-forming residues of desensitized cASIC1-SMA channels beginning at the ion channel gate. Pore profile calculated with HOLE software (pore radius: red <1.15 Å<green < 2.3 Å<purple)…
Figure 5
Elongated density within lipophilic channels at the TMD of cASIC1-SMA channels.
(a) Surface representation of cASIC1-SMA in the desensitized state colored by lipophilicity potential calculated with pyMLP (Laguerre et al., 1997) in ChimeraX (Goddard et al., 2018). (b) Hybrid …
Tables
Key resources table
Additional files
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Supplementary file 1
Cryo-EM data collection, processing and validation statistics.
- https://cdn.elifesciences.org/articles/56527/elife-56527-supp1-v2.doc
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Transparent reporting form
- https://cdn.elifesciences.org/articles/56527/elife-56527-transrepform-v2.pdf
