Thermally induced hydrogen exchange processes in small proteins as seen by FTIR spectroscopy.
Fourier-transform infrared (FTIR) spectroscopy has been used to study the thermally induced exchange characteristics of those backbone amide protons which persist H-D exchange at ambient conditions in ribonuclease A, in wild type ribonuclease T1 and some of its variants, and in the histone-like protein HBsu. The H-D exchange processes were induced by increasing the thermal energy of the protein solutions in two ways: (i) by linearly increasing the temperature, and (ii) by a temperature jump. To trace the H-D exchange in the proteins, various infrared absorption bands known to be sensitive to H-D exchange were used as specific monitors. Characteristic H-D exchange curves were obtained from which the endpoints (TH/D) of H-D exchange could be determined. The H-D exchange curves, the TH/D-values and the phase transition temperatures Tm were used to estimate the structural flexibility and stability of the given proteins. It is suggested that time-resolved FTIR spectroscopy can be used to determine global stability parameters of proteins.
Backmann
J
J
Robert Koch-Institut, Berlin, Germany.
Schultz
C
C
Fabian
H
H
Hahn
U
U
Saenger
W
W
Naumann
D
D
D000577:Amides / Q000737:chemistry; D003903:Deuterium; D006859:Hydrogen / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D011522:Protons; D012259:Ribonuclease, Pancreatic / Q000737:chemistry; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
D000577:Amides; D011506:Proteins; D011522:Protons; D012996:Solutions; D006859:Hydrogen; D003903:Deuterium; D012259:Ribonuclease, Pancreatic