Table 3. Analysis of the A20/D4 interface.

	Reference value	Difference from the reference value
Construct	WT D4/A201–50	D4/A201–50-W43A	D4-R167A/A201–50	D4-P173G/A201–50
R.m.s.d. of Cα positions compared with WT (Å)		0.29 ± 0.03	0.32 ± 0.02	0.20 ± 0.01
Buried surface (from PISA)† (Å2)	1837 ± 21	−196 ± 9	−106 ± 7	−24 ± 11
Hydrogen bonds	10	−1‡	−1‡	0
Solvation free-energy gain (from PISA)† (kcal mol−1)	−13.0 ± 0.5	2.22 ± 0.16	−1.00 ± 0.10	0.50 ± 0.06
Energy of the cation–π interaction of Trp43 (from CAPTURE)§ (kcal mol−1)	−4.2 ± 0.1	4.2 ± 0.1	4.2 ± 0.1	0.4 ± 0.3
Total of interaction energies¶ (kcal mol−1)	−17.2 ± 0.6	6.4 ± 0.3	3.2 ± 0.2	0.9 ± 0.4
Melting-temperature change (from Contesto-Richefeu et al., 2014 ▸) (°C)	47.3	−5.3	−3.6	−4.6
Complex formation upon co-expression (from Contesto-Richefeu et al., 2014 ▸)	+++	+/−	+++	++/−

^†Only residues involved in the contact around Trp43 were used in order to calculate the change. Average value for the two copies in the asymmetric unit.

^‡Loss of the hydrogen bond between the carbonyl of Thr41 and Arg167 N^η1 shown in Figs. 2 ▸(a) and 2 ▸(d).

^§Average value for the two copies in the asymmetric unit.

^¶Sum of the solvation free-energy gain and the energy of the cation–π interaction.