Regensburg 2002 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
SYBM: Physik biologischer Materie
SYBM 401: Physics of biological matter: Poster
SYBM 401.18: Poster
Dienstag, 12. März 2002, 18:00–19:30, H37
Electrostatic and Entropic Contributions to Conformational and Protonation Substates: Modelling of Proton Transfer in GFP — •Robert Raupp–Kossmann1, Sighart Fischer1, and Christina Scharnagl2 — 1Technische Universität München Lehrstuhl für Physik Weihenstephan Vöttingerstrasse 40 D-85350 Freising — 2Technische Universität München Physik–Department T38 James–Franck–Strasse 12 D-85747 Garching
The nature of the protonation reactions and the identification of internal acceptors determining the photophysics of Green Fluorescent Protein (GFP) are still subjects of debate. Our theoretical investigations analyse the thermodynamic stability of each of the four protonation states of the bifunctional fluorophore, a p-hydroxybenzylidene-imidazolidinone, in aqueous solvent and wild–type protein.
Microscopic solution pKas are calculated using a hybrid quantum classical approach and a continuum solvation model. They emphasize the role of the internal rotational degrees of freedom for adjusting the acid–base equilibrium constants.
pKa shifts in the protein are calculated using the multiconformational continuum electrostatic method extended to include multiple protonation equilibria for bifunctional groups. Additionally, these calculations reveal the energetics of relevant proton configurations and allow to explore driving forces and dipolar reorganization energies for proton transfer pathways.