Probing protein electrostatic interactions through temperature/reduction potential profiles

Autor: Eugene T. Smith, Spyros I. Nomikos, Roberto P. Christen
Rok vydání: 1996
Předmět:
Zdroj: JBIC Journal of Biological Inorganic Chemistry. 1:515-522
ISSN: 1432-1327
0949-8257
DOI: 10.1007/s007750050086
Popis: The change in the equilibrium reduction potentials of the iron-sulfur proteins, Pyrococcus furiosus rubredoxin and P. furiosus ferredoxin, and heme protein, horse cytochrome c, has been calculated as a function of temperature using a numerical solution to the Poisson-Boltzman equation. Working curves for different internal dielectric constants were generated to best reproduce experimental observation. Based on a comparison of the experimental and simulated change in reduction potential with temperature, it is concluded that the dielectric constant of proteins is temperature-dependent and varies from protein to protein. For example, the temperature-dependent reduction potential of cytochrome c can only be simulated using a different temperature-dependent dielectric constant for each oxidation state, but this was not the case for rubredoxin or ferredoxin. The role of changes in ionization states of cytochrome c at alkaline pHs, where the reduction potential is known to be pH-dependent at room temperature, is also discussed in terms of electrostatic interaction energies as a function of temperature. It appears that temperature/reduction potential profiles may provide a direct method for measuring relative changes in internal protein dielectric constants.
Databáze: OpenAIRE
Externí odkaz: