| |
 |
UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 11:53 |
 |
|
|
|
Conference: Bucharest University Faculty of Physics 2008 Meeting
Section: Electricity and Biophysics
Title:
The cation concentration dependence of protein-ligand interaction
Authors:
Alina Ene, Doina Gazdaru, A. Popescu
Affiliation:
Department of Electricity and Biophysics, Faculty of Physics, University of Bucharest
E-mail
gazdaru@rdslink.ro
Keywords:
protein-ligand interaction, affinity constant, human serum albumin, ANS, fluorescence spectroscopy
Abstract:
Protein-ligand interaction has been studied by emission fluorescence spectroscopy, the technique which is sensitive, versatile, leading itself readily to fast data acquisition.
There are two principal possibilities that can be exploited in the study of protein-ligand interactions. Both the fluorescence of the protein and of ligand can be modified after binding. This situation requires a somewhat different data analysis procedures.
Human serum albumin (HSA) and 8-anilino-1 naphtalenesulfonic acid, ammonium salt hydrate (ANS) were used in the samples containing different protein concentration (0.1 -20 μM) and constant ligand concentration (2 μM). Fluorescence emission was recorded at the emission wavelength of ANS (λem = 475 nm). Affinity constants have been determined as a function of Ca2+ concentration, using the Scatchard plots. The affinity constants were of the order of 105 M-1 and depend of cation concentration.
The protein-ligand interaction was proved to be sensitive to cation presence (e.g., Ca2+). Calcium ions could influence either the direct interaction of ligand with the fluorophore (i.e. Trp) or the interaction of the ligand with a remote site of protein.
|
|
|
|