Open AccessElectrostatic potential of macromolecules measured by p K a shift of a fluorophore
Author(s) -
FRIEDRICH Klaus,
WOOLLEY Paul,
STEINHÄUSER Klaus G.
Publication year - 1988
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1988.tb13989.x
Subject(s) - transfer rna , fluorophore , macromolecule , solvation , chemistry , fluorescence , molecule , electrostatics , fluorescein , chemical physics , rna , physics , organic chemistry , quantum mechanics , biochemistry , gene
The procedures developed earlier (Friedrich and Woolley, preceding paper in this journal) for probing electrostatic potential with the fluorescein label were applied to transfer RNA. By using tRNA species that contain chemically reactive bases we were able to label these bases with fluorescein derivatives and thus to ‘map’ the electrostatic potential around the molecule. Both the electrostatic potential and the fluorescence emission an‐isotropy data that were obtained at the same time could be understood in terms of the well‐known, paradigmatic crystal structure of tRNA Phe. However, within the distribution of the various tRNA species, tRNA f Met appeared to occupy an extreme position, which suggests a relation between the conformation in solution and the initiation function of this molecule. Comparison with theoretical predictions by others of the electrostatic potential map of tRNA showed agreement in respect of trends, but the values of the potentials measured were orders of magnitude lower than predicted. This we attribute primarily to solvation.