Table 1 Affinity and dynamic range of PfPKG biosensors for cGMP and cAMP

From: FRET-based cyclic GMP biosensors measure low cGMP concentrations in cardiomyocytes and neurons

Sensor

cGMP

cAMP

Maximal FRET change (%)

pEC50

EC50 (nM)

pEC50

EC50 (μM)

Yellow PfPKG

7.66 ± 0.07

22

5.5 ± 0.2

4.6

39 ± 3*

Cp173Venus-Venus PfPKG

7.34 ± 0.06**

46

5.4 ± 0.3

5

13 ± 3

Red PfPKG

7.58 ± 0.15

31

5.8 ± 0.2

2

10.9 ± 0.6

Red PfPKG Val536Gln

7.75 ± 0.05

18

6.2 ± 0.2

0.7

15 ± 3

Red PfPKG Val536Glu

7.59 ± 0.04

26

6.1 ± 0.1

0.8

16.0 ± 0.3

Red PfPKG Val536Asn

7.65 ± 0.12

26

5.8 ± 0.1

2

18 ± 1

Red PfPKG Val536Asp

7.76 ± 0.07

18

5.8 ± 0.1

1.5

12.1 ± 0.9

  1. HEK293 cells transfected to express the indicated biosensors were homogenized and incubated with increasing concentrations of cGMP or cAMP and fluorescence measured as described in Materials and Methods. The maximal FRET change (FCFP/FVenus or FT-Sapphire/FDimer2) was determined at the highest cGMP concentrations. EC50 shown in nM or µM were calculated from the average pEC50 (-logEC50). Results shown are mean ± SEM of 3–4 experiments
  2. *p < 0.001 vs. all other biosensors
  3. **p = 0.13 vs. Yellow PfPKG (One-way ANOVA with Dunnett’s post hoc test)
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