TABLE 1

ASIC structures

All crystal structures were obtained from chicken ASIC1. The structures 2QTS and 3HGC (4NYK) likely represent the desensitized state, whereas the other structures represent the open state. 2QTS, 3S3W, 4FZ0, and 4FZ1 display a continuous TM2 segment, whereas in 4NYK (reinterpretation of 3HGC) and 4NTW the TM2 is split in two parts by the selectivity filter GAS motif.

PDB ID	Construct	Complex with	pH	Resolution	Symmetry	Function	Reference
				Å
2QTS	N and C terminus truncated	—	5.6	1.9	∼3-fold, except in TM part	Nonfunctional	Jasti et al., 2007
3HGC ^{^a} (4NYK)	C terminus truncated	—	6.5	3.0	3-fold	Functional	Gonzales et al., 2009
3S3X	N and C terminus truncated	PcTx1	5.5	3.0	∼3-fold, except in TM part	Nonfunctional	Dawson et al., 2012
4FZ0	Truncation of 13 N-terminal and 63 C-terminal residues	PcTx1	5.5	2.8	∼3-fold, except in TM part	Functional, Na⁺-selective and amiloride-inhibited at pH 5.5	Baconguis and Gouaux, 2012
4FZ1	“	PcTx1	7.25	3.3	3-fold	Functional, nonselective, and amiloride-resistant at pH 7.25	Baconguis and Gouaux, 2012
4NTW ^{^b}	“	MitTx	5.5	2.1	3-fold	Functional, Na⁺-selective, amiloride-inhibited	Baconguis et al., 2014

↵^a Electron density of this crystal was reinterpreted in the transmembrane segment, available under PDB ID 4NYK; a structure was also obtained from these crystals soaked in Cs⁺.
↵^b Structures from this crystal were also obtained soaked in Cs⁺ (2.6 Å, 4NTY) or in amiloride (2.3 Å, 4NTX).