Trifluoroethanol-induced conformational transition of hen egg-white lysozyme studied by small-angle X-ray scattering.
The trifluoroethanol (TFE)-induced conformational transition of hen lysozyme was studied with the combined use of far-UV circular dichroism (CD) and small-angle X-ray scattering. At pH 2.0 and 20 degrees C, the addition of TFE to the native lysozyme induced a cooperative transition to an intermediate state with an increased helical content (TFE state). Small-angle X-ray scattering measurements indicated that the TFE state has a radius of gyration which is 20% larger than that of the native state and assumes a chain-like conformation with some remaining globularity. The TFE-induced transition curves obtained by CD and the small-angle X-ray scattering measurements agreed well, consistent with a two-state transition mechanism. A singular value decomposition analysis of Kratky plots of the small-angle X-ray scattering profiles indicated that two basic scattering functions reproduce the observed spectra, further confirming the validity of a two-state approximation.
Hoshino
M
M
Department of Biology, Graduate School of Science, Osaka University, Toyonaka, Japan.
Hagihara
Y
Y
Hamada
D
D
Kataoka
M
M
Goto
Y
Y
D000818:Animals; D002645:Chickens; D002942:Circular Dichroism; D004529:Egg White; D005260:Female; D009113:Muramidase / Q000737:chemistry*; D011487:Protein Conformation; D012542:Scattering, Radiation; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D014270:Trifluoroethanol / Q000737:chemistry*
D014270:Trifluoroethanol; D009113:Muramidase