Pressure effect on the stability and the conformational dynamics of the D-galactose/D-glucose-binding protein from Escherichia coli

Anna Marabotti, Petr Herman, Maria Staiano, Antonio Varriale, Marcella De Champdoré, Mosè Rossi, Zygmunt Gryczynski, Sabato D'Auria

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Abstract

The effect of the pressure on the structure and stability of the D-Galactose/D-Glucose binding protein (GGBP) from Escherichia coli was studied by steady-state and time-resolved fluorescence spectroscopy, and the ability of glucose ligand to stabilize the GGBP structure was also investigated. Steady-state fluorescence experiments showed a marked quenching of fluorescence emission of GGBP in the absence of glucose. Instead, the presence of glucose seems to stabilize the structure of GGBP at low and moderate pressure values. Time-resolved fluorescence measurements showed that the GGBP τmean in the absence of glucose varies significantly up to 600 bar, while in the presence of the ligand it is almost unaffected by pressure increase up to 600 bar. The effect of the pressure on GGBP was also studied by molecular dynamics simulations. The simulation data support the spectroscopic results and confirm that the presence of glucose is able to contrast the negative effects of pressure on the protein structure. Taken together, the spectroscopic and computer simulation studies suggest that at pressure values up to 2000 bar the structure of GGBP in the absence of glucose remains folded, but a significant perturbation of the protein secondary structures can be detected. The binding of glucose reduces the negative effect of pressure on protein structure and confers protection from perturbation especially at moderate pressure values.

Original languageEnglish
Pages (from-to)193-201
Number of pages9
JournalProteins: Structure, Function and Genetics
Volume62
Issue number1
DOIs
Publication statusPublished - 1 Jan 2006

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Keywords

  • Frequency domain
  • Glucose-binding protein
  • Molecular dynamics
  • Periplasmic protein
  • Pressure
  • Stability
  • Time-resolved fluorescence

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