TABLE 1.
All GPCR structures resolved at 3.1 Å or better, with small ions bound to 7TM domain
| Receptor | PDB code | Resolution Range, Å | Ion | Site |
|---|---|---|---|---|
| A2AAR | 4EIY, 5IU4, 5IU7, 5IU8, 5IUA, 5IUB, 5K2A, 5K2B, 5K2C, 5K2D, 5MZJ, 5MZP, 5N2R, 5NLX, 5NM2, 5NM4, 5OLG, 5OLH, 5OLV, 5OLZ, 5OM1, 5OM4, 5VRA | 1.7–2.8 | Na+ | D2.50, conserved, tight bindinga |
| DRD4 | 5WIV | 2.1 | Na+ | D2.50, conserved, tight binding |
| δ-OR | 4N6H, 4RWD | 1.8, 2.7 | Na+ | D2.50, conserved, tight binding |
| PAR1 | 3VW7 | 2.2 | Na+ | D2.50, conserved, tight binding |
| PAR2 | 5NDD | 2.8 | Na+ | D2.50, conserved, tight binding |
| CLTR1 | 6RZ4, 6RZ5 | 2.5–2.7 | Na+ | D2.50, conserved, tight binding |
| β1AR | 3ZPR, 4BVN, 5A8E | 2.1–2.7 | Na+ | D2.50, conserved, tight binding |
| β1AR | 2VT4, 2Y00, 2Y02, 2Y03, 2Y04, 2YCW, 3ZPQ, 3ZPR, 4AMJ, 4BVN, 5A8E, 6H7J, 6H7K, 6H7L, 6H7M, 6H7N, 6H7O | 2.1–3.1 | Na+ | ECL2, backbone, tight binding |
| β2AR | 4LDE, 4LDL | 2.8, 3.1 | Na+ | ECL2, backbone, tight binding |
| SMO, class F | 5L7D | 3.2 | Na+ | Loose binding |
| A2AAR | 5OM1 | 2.1 | Cl− | Helices VI and VIII (H230, R293), loose binding |
| PAR1 | 3VW7 | 2.2 | Cl- | Helices II, III, VI, (K135, R200, K307), loose binding |
| Rhodopsin | 1GZM, 1F88, 1U19, 1L9H, 1HZX, 2HPY, 2G87, 2PED, 3C9L, 3OAX | 2.2–3.0 | Zn2+ | Additive in crystallization protocols. Loose binding in multiple sites. |
| PAF | 5ZKQ | 2.9 | Zn2+ | Helices I, VI, VII (H4, H8, E259, H268), tight binding |
| SMO, class F | 4QIM, 4N4W | 2.6, 2.8 | Zn2+ | Loose binding |
| M2R | 5YC8 | 2.5 | Hg2+ | Used as anomalous scatterers for phasing. Loose binding in multiple sites. |
| Rhodopsin | 1U19, 1L9H, 1HZX, 1F88, 2PED, 2G87, 2HPY, 3OAX | 2.2–3.0 | Hg2+ | |
| 5HT2B | 6DRY, 6DRZ | 2.9, 3.1 | PO43− | Loose binding |
| DRD4 | 5WIU, 5WIV | 2, 2.1 | PO43− | ICL2 and Helix III, tight binding |
| H1R | 3RZE | 3.1 | PO43− | 7TM bundle, ECL, (K179, K191, Y431, H450), tight binding |
| μ-OR | 5C1M | 2.1 | PO43− | Loose binding |
| A2AAR | 3EML | 2.6 | SO42− | Loose binding |
| CB1 | 5U09 | 2.6 | SO42− | Loose binding |
| CCR2 | 5T1A | 2.8 | SO42− | Helix VIII, ICL1, tight binding |
| ETB1 | 5X93, 5GLI | 2.2, 2.5 | SO42− | Inside 7TM, intracellular (R199, R208, K210), tight binding, commonb |
| PD2 | 6D27, 6D26 | 2.7, 2.8 | SO42− | Inside 7TM, intracellular (R143, R2243), tight binding, commonb |
| + Other loose binding sites | ||||
| EP3 | 6M9T | 2.5 | SO42− | Loose binding |
| Rhodopsin | 3PQR, 4J4Q, 4PXF, 5DYS, 5EN0, 5TE3 | 2.3–2.9 | SO42− | Loose binding |
| β2AR | 2RH1, 5D5A | 2.4, 2.5 | SO42− | Inside 7TM, intracellular (T68, R131), tight binding, commonb |
| VI, VII (K270, K273, R328), tight binding | ||||
| μ-OR | 4DKL | 2.8 | SO42− | Inside 7TM, intracellular (T103, R179), tight binding, commonb |
| Other six loose binding sites |
a
Directly coordinated by two or more ionic interactions with charged residues.
b
SO42− bound at a common intracellular site in several receptors.