Table 3.
FRET distances from actin C374 to cTnI in cardiac thin filaments reconstituted with cTnC mutant5 D65V/D67A which does not bind regulatory Ca2+*
| Thin Filament | Thin Filament + S1-ADP | ||||
|---|---|---|---|---|---|
| Distance | Conditions | Mean Distance (Å) | Half-Width (Å) | Mean Distance (Å) | Half-Width (Å) |
| cTnI(131C)-actin(C374) | Mg2+ | 38.3 (37.1, 40.0) | 15.8 (14.2, 16,7) | 42.6 (41.3, 43.9) | 20.5 (19.3, 21.9) |
| Mg2+ + Ca2+ | 37.7 (36.5, 38.9) | 15.7 (14.3, 16.8) | 44.9 (43.8, 46.1) | 19.0 (17.9, 19.9) | |
| cTnI(151C)-actin(C374) | Mg2+ | 46.4 (45.8, 47.2) | 10.5 (9.1, 11.7) | 51.7 (50.9, 52.8) | 15.3 (13.4, 16.0) |
| Mg2+ + Ca2+ | 46.2 (45.0, 47.1) | 14.2 (13.4, 15.1) | 52.1 (51.5, 52.9) | 18.4 (16.7, 19.9) | |
| cTnI(160C)-actin(C374) | Mg2+ | 47.3 (46.5, 48.3) | 16.3 (15.8, 16.7) | 54.6 (53.7, 55.9) | 20.6 (19.7, 21.6) |
| Mg2+ + Ca2+ | 47.9 (46.8, 48.6) | 17.2 (16.8, 17.7) | 56.6 (55.3, 57.5) | 20.7 (19.6, 21.5) | |
| cTnI(167C)-actin(C374) | Mg2+ | 43.1 (42.0, 43.9) | 19.4 (18.9, 19.8) | 52.4 (51.7, 53.7) | 22.7 (21.9, 23.5) |
| Mg2+ + Ca2+ | 42.4 (41.8, 43.7) | 21.1 (20.7, 21.9) | 53.5 (52.2, 54.7) | 23.4 (21.7, 26.0) | |
| cTnI(188C)-actin(C374) | Mg2+ | 46.1 (45.3, 47.5) | 4.3 (3.9, 4.6) | 56.1 (55.2, 57.8) | 7.1 (6.6, 7.7) |
| Mg2+ + Ca2+ | 46.8 (45.3, 47.9) | 6.0 (5.7, 6.6) | 56.0 (55.1, 57.4) | 10.8 (9.9, 11.1) | |
| cTnI(210C)-actin(C374) | Mg2+ | 48.8 (47.8, 49.6) | 11.6 (10.8, 12.4) | 54.3 (53.2, 55.7) | 7.0 (6.6, 7.4) |
| Mg2+ + Ca2+ | 49.0 (48.1, 50.4) | 10.7 (9.9, 11.3) | 54.6 (53.7, 55.7) | 3.6 (3.3, 3.8) | |
• Numbers in parentheses are the lower and upper bounds of the best fitted parameters at the 68% confidence level (one standard deviation)