The Protein Journal

, Volume 29, Issue 8, pp 617–630

Planck-Benzinger Thermal Work Function: Thermodynamic Characterization of the Carboxy-Terminus of p53 Peptide Fragments

Article

DOI: 10.1007/s10930-010-9286-9

Cite this article as:
Chun, P.W. & Lewis, M.S. Protein J (2010) 29: 617. doi:10.1007/s10930-010-9286-9
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Abstract

The thermodynamic parameters for six p53 carboxy-terminus peptide fragments as determined by analytical ultracentrifugal analysis were compared over the experimental temperature range of 275–310 K to evaluate the Gibbs free energy change as a function of temperature, ΔGo(T), from 0 to 400 K using our general linear third-order fitting function, ΔGo(T) = α + βT2 + γT3. Data obtained at the typical experimental temperature range are not sufficient to accurately describe the variations observed in the oligomerization of these p53 fragments. It is necessary to determine a number of thermodynamic parameters, all of which can be precisely assessed using this general third-order linear fitting function. These are the heat of reaction, innate temperature-invariant enthalpy, compensatory temperatures and the thermodynamic molecular switch occurring at the thermal set point. This methodology can be used to distinguish the characteristic structure and stability of p53 carboxy-terminal fragments or other p53 mutants. It should be used for the thermodynamic characterization of any interacting biological system.

List of symbols

K

Kelvin, one degree on the absolute temperature scale

Tm

Melting temperature at which ΔHo(Tm) and TΔSo(Tm) intersect and the ΔGo(Tm) value reaches zero

Th

Harmonious temperature at which ΔHo(Th) and TΔSo(Th) intersect and the ΔGo(Th) value reaches zero

Ts

Thermal set point

\( T_{{C_{p} }} \)

Temperature at which ΔCpo(T) value reaches zero

IMSL

International mathematical subroutine library

S

Entropy

H

Enthalpy

A

Helmholtz free energy

ΔGo(T)

Gibbs free energy change as a function of temperature

ΔWo(T)

Heat flux term

ΔWo(T) = ΔHo(T0) − ΔGo(T)

Planck-Benzinger thermal work function

ΔHo(T0)

Innate temperature-invariant enthalpy

φ

Effective free energy from the partition function

Keq

Equilibrium constant

ΔCp(T)(+) → ΔCp(T)(−)

Thermodynamic molecular switch at which the Gibbs free energy of reaction reaches a true negative minimum, changing in sign from positive to negative

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.Department of Biochemistry and Molecular Biology, College of MedicineUniversity of FloridaGainesvilleUSA
  2. 2.Analytical Ultracentrifugation by Marc S. Lewis, formerly of the Biomedical Engineering and Instrumentation ProgramNational Center for Research ResourcesBethesdaUSA