Table 1.

Theoretical and biophysical data for p53tet

Amino acid	Molecular weight*	Molecular weight apparent†	Sigma	N‡	Tm§	ΔE¶	Hydrophobicity‖
Mutations at residue 340
Met (WT)					85**	22.2	1.68
Ser	8,103	32,370	3,000	4.0	59	13.3	−0.05
Gln	8,144	33,730	3,250	4.1	62	8.6	−0.30
Ala**				4	55	13.4	0.18
His	8,153	27,790	2,350	3.4	58	11.1	0.18
Lys	8,144	30,440	2,830	3.4	66	2.5	−1.35
Glu	8,145	16,630	1,000	2.0	34	3.8	−0.87
Asp	8,131	15,870	1,000	2.0	38	11.3	−1.05
Mutations at residue 344
Leu (WT)					85**	22.2	1.68
Ala	6,080‡‡	15,840	2,500	2.6	49	5.4	0.18
Ala**				2	47	5.4	0.18
Gln	8,880	19,260	2,500	2.2	50	N/A	−0.30
Arg	8,910	17,970	2,700	2.0	43	N/A	−0.05
Lys	8,880	18,240	2,050	2.1	48	N/A	−1.35

^*Theoretical molecular weight of the monomeric protein. The difference between the 8.8- and 8.1-kDa proteins is in the size of the polyhistidine tag. 

^† Apparent molecular weight (Da) as determined by laser light scattering at concentrations of 200–500 μM. Sigma is one standard deviation in Da. 

^‡ N is the apparent molecular weight divided by the monomeric molecular weight and for proteins that are a single oligomeric state, N is equal to the oligomeric state. 

^§ Melting temperature in °C at 100 μM protein concentration as described in Materials and Methods. 

^¶ ΔE is the depth of the energy minima, i.e., the difference between the free energy at infinite separation minus the minimal possible energy of the tetramer. 

^‖Hydrophobicity index of Eisenberg and McLachlan (34), determined at a concentration of 57 μM. 

^**Melting temperature in °C at 10 μM protein concentration, from ref. 8. 

^‡‡This mutant was soluble only with the polyhistidine tag removed, thus the lower molecular weight.