Using buried water molecules to explore the energy landscape of proteins.
Buried water molecules constitute a highly conserved, integral part of nearly all known protein structures. Such water molecules exchange with external solvent as a result of protein conformational fluctuations. We report here the results of water (17)O and (2)H magnetic relaxation dispersion measurements on wild-type and mutant bovine pancreatic trypsin inhibitor in aqueous solution at 4-80 degrees C. These data lead to the first determination of the exchange rate of a water molecule buried in a protein. The strong temperature dependence of this rate is ascribed to large-scale conformational fluctuations in an energy landscape with a statistical ruggedness of approximately 10 kJ mol(-1).
Denisov
V P
VP
Condensed Matter Magnetic Resonance Group, Department of Chemistry, Lund University, Lund, Sweden.
Peters
J
J
Hörlein
H D
HD
Halle
B
B
D007611:Aprotinin / Q000737:chemistry* / Q000235:genetics; D004735:Energy Transfer; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D013696:Temperature; D014867:Water / Q000737:chemistry* / Q000378:metabolism
D014867:Water; D007611:Aprotinin