Table 3. IANBD-cTnC T53C fluorescence... | Rockefeller University Press

Table 3.

IANBD-cTnC^T53C fluorescence lifetime changes with myosin in weakly and strongly bound states

Experiment (N)	Buffer condition*	Myosin-binding	Average lifetime	SD	C.V.	n	Change + Ca²⁺	Z′	P
#1	ATP, low Ca²⁺	Weak	2.53	0.01	0.5%	23
	^@ADP, high Ca²⁺	Strong	2.36	0.02	0.9%	23	−6.7%	0.39	2.3 × 10⁻³²
#2	ATP, low Ca²⁺	Weak	2.61	0.01	0.5%	23
	^@ADP, high Ca²⁺	Strong	2.42	0.02	0.8%	22	−7.2%	0.47	1.2 × 10⁻³⁴
#3	ATP, low Ca²⁺	Weak	2.56	0.02	0.7%	24
	^@ADP, high Ca²⁺	Strong	2.28	0.03	1.4%	24	−10.8%	0.44	3.1 × 10⁻³⁵
#4	ATP, low Ca²⁺	Weak	2.56	0.04	1.5%	12
	^@ADP, high Ca²⁺	Strong	2.36	0.03	1.4%	12	−8.2%	−0.02	1.4 × 10⁻¹²
Avg	ATP, low Ca²⁺	Weak	2.56	−	−
	^@ADP, high Ca²⁺	Strong	2.35	−	−		−8.2%	0.32	3.4 × 10⁻¹³

Experiment (N)	Buffer condition*	Myosin-binding	Average lifetime	SD	C.V.	n	Change + Ca²⁺	Z′	P
#1	ATP, low Ca²⁺	Weak	2.53	0.01	0.5%	23
	^@ADP, high Ca²⁺	Strong	2.36	0.02	0.9%	23	−6.7%	0.39	2.3 × 10⁻³²
#2	ATP, low Ca²⁺	Weak	2.61	0.01	0.5%	23
	^@ADP, high Ca²⁺	Strong	2.42	0.02	0.8%	22	−7.2%	0.47	1.2 × 10⁻³⁴
#3	ATP, low Ca²⁺	Weak	2.56	0.02	0.7%	24
	^@ADP, high Ca²⁺	Strong	2.28	0.03	1.4%	24	−10.8%	0.44	3.1 × 10⁻³⁵
#4	ATP, low Ca²⁺	Weak	2.56	0.04	1.5%	12
	^@ADP, high Ca²⁺	Strong	2.36	0.03	1.4%	12	−8.2%	−0.02	1.4 × 10⁻¹²
Avg	ATP, low Ca²⁺	Weak	2.56	−	−
	^@ADP, high Ca²⁺	Strong	2.35	−	−		−8.2%	0.32	3.4 × 10⁻¹³

Average data are provided for individual experiments. Experiments were carried out with three separate protein preparations of troponin that was exchanged into four separate myofibril preparations. Low Ca²⁺ is pCa 9 and High Ca²⁺ is pCa 4.5. The unit for Average (fluorescence) lifetime and SD (standard deviation) is nanoseconds. n = number of wells of myofibrils (in rigor buffer) into which ATP and low or high Ca²⁺ is individually added and scanned at 20 min, following an initial scan in rigor buffer (Change + Ca²⁺). C.V. is the coefficient of variance. Statistical tests of Z′ factor and t test are used to evaluate the change in lifetime between low and high Ca²⁺ in the presence of ATP. ^@ADP, high Ca²⁺ buffer condition indicates that 0.1 mM ATP was added in pCa 4.5 and after 20 min, all ATP was hydrolyzed to ADP due to ATPase activity of myofibrils (see Fig. 1 C and Function of IANBD-cTnC^T53C-exchanged myofibril preparations). The average Z′ and percentage Changes from Weak to Strong myosin-binding for the four experiments is also given.

View Large

This Feature Is Available To Subscribers Only