TABLE 3.

Structures of human M1, M2, and M4 receptors, and rat M3 receptor

Receptor	PDB ID	Ligand	Efficacy	Fusion Partner	Resolution (Å)	References
M1R	5CXV	Tiotropium	Inverse agonist	T4 lysozyme (T4L) in ICL3	2.70	Thal et al., 2016
M2R	3UON	QNB	Inverse agonist	T4L in ICL3	3.00	Haga et al., 2012
M2R	4MQS	Iperoxo	Full agonist	None	3.50	Kruse et al., 2013a
M2R	4MQT	Iperoxo, LY2119620	Full agonist, PAM	None	3.70	Kruse et al., 2013a
M2R	5ZK8	NMS	Inverse agonist	Cytochrome b562RIL (BRIL) in ICL3	3.00	Suno et al., 2018
M2R (S110R)	5ZKC	NMS	Inverse agonist	BRIL in ICL3	2.30	Suno et al., 2018
M2R (S110R)	5ZKB	AF-DX 384	Antagonist	BRIL in ICL3	2.95	Suno et al., 2018
M2R (S110R)	5ZK3	QNB	Inverse agonist	BRIL in ICL3	2.60	Suno et al., 2018
M2R (S110R)	5YC8	NMS, Hg	Inverse agonist, cation	BRIL in ICL3	2.50	Suno et al., 2018
M3R	4DAJ	Tiotropium	Inverse agonist	T4L in ICL3	3.40	Kruse et al., 2012
M3R	4U14	Tiotropium	Inverse agonist	Disulfide stabilized T4L in ICL3	3.57	Thorsen et al., 2014
M3R	4U15	Tiotropium	Inverse agonist	Minimal T4L (mT4L) in ICL3	2.80	Thorsen et al., 2014
M3R	4U16	NMS	Inverse agonist	mT4L in ICL3	3.70	Thorsen et al., 2014
M3R	5ZHP	Compound 6o (BS46)	Antagonist	mT4L in ICL3	3.10	Liu et al., 2018
M4R	5DSG	Tiotropium	Inverse agonist	mT4L in ICL3	2.60	Thal et al., 2016