Molecular dynamics of two homologous neurotoxins revealed by 1H-2H exchange: an infrared spectrometry study.
Temperature effects on the hydrogen exchange kinetics and the infrared spectra of two homologous snake neurotoxins (Laticauda semifasciata erabutoxin b and Naja nigricollis toxin alpha) were investigated between 10 and 40 degrees C, at their isoionic pH. (1) Erabutoxin b is more accessible to the solvent than toxin alpha. (2) With increasing temperature, both toxin molecules undergo a global transition affecting the most accessible as well as the most buried hydrogens: the overall accessibility changes are more important for erabutoxin b than for toxin alpha. The different conformational stabilities of the toxins are also qualitatively supported by the temperature-induced shifts which affect the infrared amide I band of toxin alpha only. The existence of two conformer families could be responsible for the different conformational stability of these proteins.
D000818:Animals; D003039:Cobra Neurotoxin Proteins; D003903:Deuterium; D004546:Elapid Venoms; D004870:Erabutoxins; D006859:Hydrogen; D008968:Molecular Conformation; D012911:Snakes; D013055:Spectrophotometry, Infrared; D013816:Thermodynamics
D003039:Cobra Neurotoxin Proteins; D004546:Elapid Venoms; D004870:Erabutoxins; C025154:alpha-cobratoxin; D006859:Hydrogen; D003903:Deuterium