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. Author manuscript; available in PMC: 2008 Dec 16.
Published in final edited form as: Biochemistry. 2008 Dec 16;47(50):13383–13393. doi: 10.1021/bi801492x

Table 2.

FRET distances between actin(C374) and cTnI in regulated cardiac thin filaments

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+ 37.3 (36.3,
38.5)		 12.8 (11.2,
13,7)		 41.4 (40.0,
42.9)		 15.0 (13.9,
16.3)
Mg2+ +
Ca2+ 		39.0 (38.1,
40.3)		 15.1 (14.3,
16.4)		 44.0 (42.8,
45.1)		 21.5 (20.3,
22.9)
cTnI(151C) -
actin(C374)		 Mg2+ 43.5 (42.8,
44.2)		 13.0 (12.1,
13.7)		 53.9 (52.6,
55.1)		 18.0 (16.9,
19.6)
Mg2+ +
Ca2+ 		54.6 (53.2,
55.8)		 17.1 (16.3,
17.8)		 56.8 (55.6,
57.8)		 22.7 (20.9,
23.3)
cTnI(160C)-
actin(C374)		 Mg2+ 47.1 (45.9,
48.0)		 19.5 (18.2,
20.8)		 56.3 (54.0,
58.1)		 21.6 (20.2,
22.8)
Mg2+ +
Ca2+ 		57.3 (56.3,
58.6)		 14.6 (12.4,
16.3)		 59.8 (58.3,
61.7)		 15.2 (13.6,
17.1)
cTnI(188C)-
actin(C374)		 Mg2+ 40.8 (39.3,
41.7)		 19.0 (18.1,
20.3)		 54.3 (53.8,
55.9)		 23.2 (21.9,
24.1)
Mg2+ +
Ca2+ 		53.1 (52.2,
54.3)		 15.2 (14.3,
16.6)		 60.7 (59.2,
62.2)		 17.3 (15.9,
18.4)
cTnI(167C)-
actin(C374)		 Mg2+ 46.7 (45.8,
47.7)		 6.6 (6.1, 7.3) 53.7 (52.1,
55.3)		 6.8 (6.2, 7.3)
Mg2+ +
Ca2+ 		51.3 (50.2,
52.5)		 8.6 (7.8,
10.2)		 58.4 (57.2,
59.6)		 9.6 (8.7,
11.2)
cTnI(210C)-
actin(C374)		 Mg2+ 47.3 (46.1,
48.4)		 5.4 (4.9, 5.8) 54.2 (53.2,
55.2)		 4.9 (4.3, 5.6)
Mg2+ +
Ca2+ 		53.1 (52.0,
54.3)		 7.2 (6.4, 8.3) 57.5 (56.4,
59.0)		 8.4 (6.9, 9.8)

• Numbers in parentheses are the lower and upper bounds of the best fitted parameters at the 68% confidence level (one standard deviation).

• Thin Filament + S1-ADP was prepared by mixing each troponin component at a ratio of one cTn, one cTm, 7.5 polymerized actin, and seven S1-ADP (see Materials and Methods).