TY - JOUR
T1 - Binding of glucose to the D-galactose/D-glucose-binding protein from Escherichia coli restores the native protein secondary structure and thermostability that are lost upon calcium depletion
AU - D'Auria, Sabato
AU - Ausili, Alessio
AU - Marabotti, Anna
AU - Varriale, Antonio
AU - Scognamiglio, Viviana
AU - Staiano, Maria
AU - Bertoli, Enrico
AU - Rossi, Mosè
AU - Tanfani, Fabio
PY - 2006/2
Y1 - 2006/2
N2 - The effect of the depletion of calcium on the structure and thermal stability of the D-galactose/D-glucose-binding protein (GGBP) from Escherichia coli was studied by fluorescence spectroscopy and Fourier-transform infrared spectroscopy. The calcium-depleted protein (GGBP-Ca) was also studied in the presence of glucose (GGBP-Ca/Glc). The results show that calcium depletion has a small effect on the secondary structure of GGBP, and, in particular it affects a population of α-helices with a low exposure to solvent. Alternatively, glucose-binding to GGBP-Ca eliminates the effect induced by calcium depletion by restoring a secondary structure similar to that of the native protein. In addition, the infrared and fluorescence data obtained reveal that calcium depletion markedly reduces the thermal stability of GGBP. In particular, the spectroscopic experiments show that the depletion of calcium mainly affects the stability of the C-terminal domain of the protein. However, the binding of glucose restores the thermal stability of GGBP-Ca. The thermostability of GGBP and GGBP-Ca was also studied by molecular dynamics simulations. The simulation data support the spectroscopic results. New insights into the role of calcium in the thermal stability of GGBP contribute to a better understanding of the protein function and constitute important information for the development of biotechnological applications of this protein. Mutations and/or labelling of amino acid residues located in the protein C-terminal domain may affect the stability of the whole protein structure.
AB - The effect of the depletion of calcium on the structure and thermal stability of the D-galactose/D-glucose-binding protein (GGBP) from Escherichia coli was studied by fluorescence spectroscopy and Fourier-transform infrared spectroscopy. The calcium-depleted protein (GGBP-Ca) was also studied in the presence of glucose (GGBP-Ca/Glc). The results show that calcium depletion has a small effect on the secondary structure of GGBP, and, in particular it affects a population of α-helices with a low exposure to solvent. Alternatively, glucose-binding to GGBP-Ca eliminates the effect induced by calcium depletion by restoring a secondary structure similar to that of the native protein. In addition, the infrared and fluorescence data obtained reveal that calcium depletion markedly reduces the thermal stability of GGBP. In particular, the spectroscopic experiments show that the depletion of calcium mainly affects the stability of the C-terminal domain of the protein. However, the binding of glucose restores the thermal stability of GGBP-Ca. The thermostability of GGBP and GGBP-Ca was also studied by molecular dynamics simulations. The simulation data support the spectroscopic results. New insights into the role of calcium in the thermal stability of GGBP contribute to a better understanding of the protein function and constitute important information for the development of biotechnological applications of this protein. Mutations and/or labelling of amino acid residues located in the protein C-terminal domain may affect the stability of the whole protein structure.
KW - Galactose/glucose-binding protein
KW - Infrared spectroscopy
KW - Protein stability
KW - Protein structure
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U2 - 10.1093/jb/mvj027
DO - 10.1093/jb/mvj027
M3 - Article
C2 - 16452309
AN - SCOPUS:33645297396
VL - 139
SP - 213
EP - 221
JO - Journal of Biochemistry
JF - Journal of Biochemistry
SN - 0021-924X
IS - 2
ER -