Table 1 Helicity and thermodynamic parameters for the p53-peptides from the CD data, TFE-titration curves and MD simulations^a.

p53-peptide	[TFE]_1/2 (%)	m (cal mol⁻¹(%)⁻¹)	% Helix in water (from ΔG in TFE titrations)^c	% Helix in water ([Θ]₂₂₂)^d	% Helix from REMD
Ac-ETFSDLWKLLPEN-NH₂ (P53-WT)	7 ± 7	130 ± 50	16 ± 3	8.7 (−2741)	7
Ac-EptFpsDLWKLLPEN-NH₂ (P53-pTpS)^b				8.1 (−2547)	2.1
Ac-EptFSDLWKLLPEN-NH₂ (P53-pT)^b				10.2 (−3213)	2
Ac-ETFpsDLWKLLPEN-NH₂ (P53-pS)^b				14.6 (−4614)	15
Ac-EeFSDLWKLLPEN-NH₂ (P53-E18)	14 ± 5	103 ± 42	7 ± 1	7.5 (−2380)	2.8
Ac-ETFdDLWKLLPEN-NH₂ (P53-D20)	25 ± 3	74 ± 32	4 ± 2	9 (−2811)	7.6
Ac-EeFdDLWKLLPEN-NH₂ (P53-E18-D20)	15 ± 1	135 ± 18	3 ± 1	6.6 (−2100)	6.7
Ac-EeFdDLWeeLPEN-NH₂ (P53-E18-D20-E24-E25)^b				0 (142.7)
Ac-EeFeDLWKLLPEN-NH₂ (P53-E18-E20)	24.5 ± 0.9	420 ± 390	1	8.7 (−2757)	5
Ac-EdFSDLWKLLPEN-NH₂ (P53-D18)	12.0 ± 0.7	383 ± 142	1	10.5 (−3313)	2.5
Ac-ETFeDLWKLLPEN-NH₂ (P53-E20)	25 ± 2	231 ± 141	1	9.2 (−2911)	10
Ac-EdFeDLWKLLPEN-NH₂ (P53-D18-E20)	33 ± 5	112 ± 70	1	11.4 (−3597)	6
Ac-EdFdDLWKLLPEN-NH₂ (P53-D18-D20)	9.8 ± 0.8	263 ± 47	1	9 (−2811)	4.7

^aExperiments were carried out at 5 °C in phosphate buffer (pH 6.8, 50 mM). Data errors are fitting errors to a two-state equation³². Mutations (or phosphorylated residues) are indicated in bold in lower case lettering. Final concentrations of the peptides for the titrations were 40 μM.
^bThe TFE-titration curves for the peptides were very flat, i.e. there was a decrease in the ellipticity as the [TFE] increased, but the curves did not have a sigmoidal shape.
^cDetermined from the value of the free energy in aqueous solution (ΔG = [TFE]_1/2 × m). For the peptides with a 1% percentage the error was 10%.
^dDetermined from the values of the molar ellipticity at 222 nm (within the parentheses for each peptide), assuming that a 100% helical peptide has a mean residue ellipticity of −31500 deg cm² dmol⁻¹ ²⁷.

Quick links

Search