Protein Free Energy Landscapes Remodeled by Ligand Binding

Document Type

Article

Publication Date

1-1-2007

Journal / Book Title

Biophysical Journal

Abstract

Glucose/galactose binding protein (GGBP) functions in two different larger systems of proteins used by enteric bacteria for molecular recognition and signaling. Here we report on the thermodynamics of conformational equilibrium distributions of GGBP. Three fluorescence components appear at zero glucose concentration and systematically transition to three components at high glucose concentration. Fluorescence anisotropy correlations, fluorescent lifetimes, thermodynamics, computational structure minimization, and literature work were used to assign the three components as open, closed, and twisted conformations of the protein. The existence of three states at all glucose concentrations indicates that the protein continuously fluctuates about its conformational state space via thermally driven state transitions; glucose biases the populations by reorganizing the free energy profile. These results and their implications are discussed in terms of the two types of specific and nonspecific interactions GGBP has with cytoplasmic membrane proteins.

Comments

This article is Open Access under an Elsevier User License.

DOI

10.1529/biophysj.107.103911

This document is currently not available here.

Link to Publisher

Share

COinS