Table 1.
Distances (in Angstroms) obtained by DEER between C2A and C2B.†
| C2A/C2B mutant | *Ca2+ | EGTA | *POPC:POPS |
|---|---|---|---|
| M173R1/V304R1 | 39±9 | 41±13 | 38±19 |
| M173R1/K332R1 | 45±10 | 46±9 | 46±11 |
| R199R1/V304R1 | 37±16 | 39±15 | 40±14 |
| R199R1/K332R1 | 46±9 | 47±8 | 46±8 |
| R199R1/I367R1 | 43±5 | 44±5 | -- |
| F234R1/V304R1 | 33±11 | 36±9 | 27±18 |
| F234R1/K332R1 | 42±14 | 41±13 | 44±12 |
| K189R1/K327R1 | 43±12 | -- | 43±11 |
| K213R1/K327R1 | 50±7 | -- | 48±5 |
| K213R1/V283R1 | 60±18 | 61±16 | |
| K213R1/T285R1 | 60±10 | 62±12 | |
| K213R1/Q353R1 | 54±13 | 56±15 | |
| K244R1/K327R1 | 41±11 | -- | 45±10 |
Distances represent Gaussian fits to the distance distributions determined using the program DEER analysis 46. The range given represents the standard deviation to the Gaussian fit. For most of the distances, the uncertainty in the distance is estimated to be approximately 2 to 3 Angstroms, and the uncertainty in the distribution is approximately 30%. The R199R1/I367R1 pair labeled poorly, and the distances measured from K213R1 are long. For these five mutant pairs, there is approximately a 4 Å distance uncertainty and a 50% uncertainty in the distribution.
Data for the Ca2+-bound aqueous and the membrane-bound forms of syt1C2AB were used to determine a family of structures using simulated annealing.