Pressure affects the structure and the dynamics of the D-galactose/D-glucose-binding protein from Escherichia coli by perturbing the C-terminal domain of the protein.
The effect of the pressure on the structure and stability of the D-galactose/D-glucose binding protein from Escherichia coli in the absence (GGBP) and in the presence (GGBP/Glc) of glucose was studied by Fourier transform infrared (FT-IR) spectroscopy and molecular dynamic (MD) simulations. FT-IR spectroscopy experiments showed that the protein beta-structures are more resistant than alpha-helices structures to pressure value increases. In addition, the infrared data indicated that the binding of glucose stabilizes the protein structure against high pressure values, and the protein structure does not completely unfold up to pressure values close to 9000 bar. MD simulations allow a prediction of the most probable configuration of the protein, consistent with the increasing pressures on the two systems. The detailed analysis of the structures at molecular level confirms that, among secondary structures, alpha-helices are more sensitive than beta-structures to the destabilizing effect of high pressure and that glucose is able to preserve the structure of the protein in the complex. Moreover, the evidence of the different resistance of the two domains of this protein to high pressure is investigated and explained at a molecular level, indicating the importance of aromatic amino acid in protein stabilization.
Marabotti
Anna
A
Laboratorio di Bioinformatica, Istituto di Scienze dell'Alimentazione, CNR, Avellino, Italy.
Ausili
Alessio
A
Staiano
Maria
M
Scirè
Andrea
A
Tanfani
Fabio
F
Parracino
Antonietta
A
Varriale
Antonio
A
Rossi
Mosè
M
D'Auria
Sabato
S
D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D005690:Galactose / Q000737:chemistry; D005947:Glucose / Q000737:chemistry; D009004:Monosaccharide Transport Proteins / Q000737:chemistry*; D011312:Pressure; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
D029968:Escherichia coli Proteins; D009004:Monosaccharide Transport Proteins; C509064:mglB protein, E coli; D005947:Glucose; D005690:Galactose