. Author manuscript; available in PMC: 2014 Jul 23.

Published in final edited form as: Biochemistry. 2013 Jul 15;52(29):10.1021/bi400320s. doi: 10.1021/bi400320s

Table 1.

Melting temperatures for N-terminal NFU, C-terminal NFU, a mixture of N- and C-terminal domains, and full-length NFU determined by DSC.

	[NaCl] (mM)	T_m1 (°C)	T_m2 (°C)	T_m2 -T_m1 (°C)	T_m3 (°C)	T_m4 (°C)	T_m4 -T_m3 (°C)
N-NFU	100.0	74.7 ± 0.6	78.4 ± 0.1	3.7	-	-	-
N-NFU	0.0	75.0 ± 0.6	80.0 ± 0.1	5.1	-	-	-
C-NFU	100.0	57-80	57-80	-	-	-	-
C-NFU	0.0	49-81	49-81	-	-	-	-
N-NFU / C-NFU	100.0	49.3 ± 0.3	58.1 ± 0.4	8.8	78.0 ± 1.5	80.6 ± 0.2	2.6
N-NFU / C-NFU	0.0	28.7 ± 0.7	41.4 ± 0.7	12.7	76.6 ± 0.5	80.9 ± 0.1	4.3
NFU	100.0	63.3 ± 3.4	67.0 ± 0.3	3.7	75.6 ± 7.9	77.1 ± 3.7	1.5
NFU	0.0	51.3 ± 0.6	58.1 ± 2.6	6.7	69.4 ± 4.9	76.1 ± 1.2	6.7

For a well-folded N-terminal domain, the change in melting temperatures for secondary and tertiary structures Δ (T_m^ter-T_m^sec) is inversely related to the ionic strength. The majority of this observation is contributed by the decrease in T_m^sec at lower ionic strength.