A 2D-IR study of heat- and [(13)C]urea-induced denaturation of sarcoplasmic reticulum Ca(2+)-ATPase.
Two-dimensional infrared correlation spectroscopy (2D-IR) was applied to the study of urea- and heat-induced unfolding denaturation of sarcoplasmic reticulum Ca(2+)-ATPase (SR ATPase). Urea at 2-3 M causes reversible loss of SR ATPase activity, while higher concentrations induce irreversible denaturation. Heat-induced denaturation is a non-two-state process, with an "intermediate state" (at t approximately 45 degrees C) characterized by the presence of protein monomers, instead of the native oligomers. 2D-IR reveals that urea denaturation causes loss of the structural transition to the "intermediate state". Whenever the urea effect can be reversed, the transition to the "intermediate state" is re-established.
Unidad de Biofísica (Centro Mixto CSIC-UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain.
Ibón
I
Iloro
Félix M
FM
Goñi
José L R
JL
Arrondo
D000818:Animals; D006358:Hot Temperature; D017510:Protein Folding / Q000187:drug effects; D011817:Rabbits; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013696:Temperature; D014508:Urea / Q000494:pharmacology*
D014508:Urea; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases