Structural and thermal stability characterization of Escherichia coli D-galactose/D-glucose-binding protein.
The effect of temperature and glucose binding on the structure of the galactose/glucose-binding protein from Escherichia coli was investigated by circular dichroism, Fourier transform infrared spectroscopy, and steady-state and time-resolved fluorescence. The data showed that the glucose binding induces a moderate change of the secondary structure content of the protein and increases the protein thermal stability. The infrared spectroscopy data showed that some protein stretches, involved in alpha-helices and beta strand conformations, are particularly sensitive to temperature. The fluorescence studies showed that the intrinsic tryptophanyl fluorescence of the protein is well represented by a three-exponential model and that in the presence of glucose the protein adopts a structure less accessible to the solvent. The new insights on the structural properties of the galactose/glucose-binding protein can contribute to a better understanding of the protein functions and represent fundamental information for the development of biotechnological applications of the protein.
D'Auria
Sabato
S
University of Maryland at Baltimore, Center for Fluorescence Spectroscopy, 725 W Lombard Street, Baltimore Maryland 21201, USA. dauria@dafne.ibpe.na.cnr.it
Alfieri
Fabrizio
F
Staiano
Maria
M
Pelella
Fabrizio
F
Rossi
Mose'
M
Scirè
Andrea
A
Tanfani
Fabio
F
Bertoli
Enrico
E
Grycznyski
Zigmunt
Z
Lakowicz
Joseph R
JR
D003198:Computer Simulation; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000032:analysis* / Q000737:chemistry*; D008958:Models, Molecular; D009004:Monosaccharide Transport Proteins / Q000032:analysis* / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D013696:Temperature
D029968:Escherichia coli Proteins; D009004:Monosaccharide Transport Proteins