Protein-Ligand Interactions of the D-Galactose/D-Glucose-Binding Protein as a Potential Sensing Probe of Glucose Biosensors
Figure 1
GdnHCl and heat-induced denaturation of GGBP in the presence and in the absence of its ligands—calcium and glucose. (a) Equilibrium dependencies of fluorescence intensity at 320 nm of GGBP and GGBP-Ca (black and gray circles, resp.) and GGBP/Glc and GGBP-Ca/Glc (black and gray squares, resp.). Open symbols: unfolding, closed: refolding, nm. (b) The change of parameter at protein unfolding and refolding. Unfolding curves were measured for GGBP after incubation in solutions of an appropriate denaturant concentration at 4°C during 24 h (gray solid line and gray open circles) and for GGBP/Glc after incubation during 24 h (black dashed line and black open squares) and 10 days (black solid line and black open circles). Date characterizing protein renaturation from unfolded state was measured after incubation in solution of an appropriate denaturant concentration at 4°C during 24 h for GGBP (gray closed circles) and during 24 h (black closed squares) and 10 days for GGBP/Glc (black closed cicles), nm. (c) Temperature dependencies of the excess heat capacity of GGBP (gray) and GGBP/Glc (black). (d) Heat-incubation denaturation of GGBP (gray) and GGBP/Glc (black) as recorded by fluorescence experiments. Two sequential scans (solid and dashed lines, resp.) are shown to characterize the reversibility of the thermal transitions, nm.
