Table 1.

Summary of the mutants studied in this work

	Hemoglobin	Interface	K2,4* (M−1) × 10−4	Δ(ΔG0)† kcal/mol
	HbA		100 ± 25	0 ± 0.28
1	α38Thr → Trp + α103His → Val	α1β2 (switch) + α1β1 (stationary)	550  ±  130	−0.96  ±  0.27
2	α38Thr → Trp	α1β2 (switch)	400  ±  100	−0.78  ±  0.28
3	α38Thr → Trp + α41Thr → Arg	α1β2 (switch)	340  ±  90	−0.68  ±  0.29
4	α103His → Val	α1β1 (stationary)	70  ±  30	+0.2  ±  0.38
5	α41Thr → Arg	α1β2 (switch)	13  ±  3	+1.14  ±  0.27
6	β40Arg → Thr	α1β2 (hinge)	2.4  ±  0.4	+2.1  ±  0.23
7	α38Thr → Trp+β37Trp → Thr	α1β2 (switch + hinge)	2.0  ±  0.5	+2.2  ±  0.28
8	β37Trp → Thr	α1β2 (switch)	fully dimer (<40 μM)	+3

We report the interface where the mutation is located and, for the α₁β₂ interface, the indication of the “switch” or the “hinge” region (2). 

^*K_2,4 is given as mean ± SD. 

^†Δ(ΔG_i⁰) = ΔG_m⁰ − ΔG_wt⁰, where m and wt stand for mutant and wild-type Hb, respectively. The errors in Δ(ΔG⁰) were calculated following the error propagation theory (42) and in particular the formulas: q(x) ± δq = q(x_best) ± |dq(x)/dx|δx and q ± δq = (x − y) ± (δx + δy), where q(x) is a function of a variable measured with errors, δq, δx, and δy are the errors associated to q(x), x, and y, respectively, and dq(x)/dx is the first derivative of the function q(x) with respect to the variable x.