Table 1.
GAF binding properties of cGMP analogues
| Analogue | EC50(µM) PDE2-GAF | EC50(µM) PDE5-GAF |
|---|---|---|
| cGMP | 0.042 (0.023–0.075) | 0.065 (0.048–0.090) |
| cAMP | 2.4 (1.0–5.4) | – |
| 2-NH2-cPuMP | 0.71 (0.27–1.87) | 3.5 (2.2–5.7) |
| 8-AET-cGMP | – | – |
| 8-APT-cGMP | – | – |
| 1-NH2-cGMP | 4.9 (2.1–11.1) | >100 |
| 2′-AHC-cGMP | – | – |
| Sp-2′-AHC-cGMPS | – | – |
| 8-Br-cGMP | – | 0.56 (0.42–0.74) |
| Rp-8-Br-cGMPS | – | >100 |
| Sp-8-Br-cGMPS | – | 2.7 (1.4–5.4) |
| 8-pCPT-cGMP | >100 | >100 |
| Rp-8-pCPT-cGMPS | – | – |
| Sp-8-pCPT-cGMPS | – | – |
| Rp-8-pCPT-PET-cGMPS | – | – |
| Sp-8-pCPT-PET-cGMPS | – | – |
| 5,6-DM-cBIMP | 0.10 (0.035–0.28) | – |
| DB-cGMP | 3.8 (1.2–11) | – |
| 5,6-DCl-cBIMP | 0.28 (0.12–0.65) | >100 |
| Sp-5,6-DCl-cBIMPS | 19 (7–50) | – |
| 2′-dcGMP | 3.5 (1.3–9.4) | 1.9 (1.2–3.0) |
| Rp-cGMPS | 6.2 (1.8–21) | 3.3 (2.2–5.2) |
| Sp-cGMPS | >100 | 26 (18–35) |
| cIMP | 0.72 (0.33–1.6) | 0.32 (0.21–0.48) |
| MANT-cGMP | 8.2 (2.6–26) | 4.5 (1.2–17) |
| 2′-O-MS-cGMP | 2.5 (0.9–6.4) | 0.62 (0.41–0.93) |
| 2′-O-MS-TME-cGMP | 0.22 (0.08–0.64) | 0.20 (0.11–0.37) |
| 2′-O-ME-cGMP | 28 (15–53) | 47 (23–95) |
| PET-cGMP | 0.35 (0.13–0.89) | 3.2 (1.1–9.2) |
| 8-Br-PET-cGMP | – | >100 |
| Rp-8-Br-PET-cGMPS | – | – |
| Sp-8-Br-PET-cGMPS | – | – |
| cPuMP | 8.0 (2.7–23.7) | – |
| cXMP | >100 | 70 (38–129) |
The half-maximally effective concentrations (EC50) of different cGMP analogues that elicit conformational changes of the GAF domains of PDE2 and PDE5 are presented. Conformational changes were assessed by in vitro recording of fluorescence resonance energy transfer (FRET) between two fluorescent proteins fused to the GAF domains. EC50 values given were calculated from at least three independent determinations performed in duplicate; 95% confidence intervals of the EC50 values are given in parentheses. –, no FRET change detectable at a concentration of 100 µM of the analogue. Full chemical names and structures of the analogues are listed in Table S1 and Figure S1.