Conformational change in a single molecular species, beta3, of beta-conglycinin in acidic ethanol solution.
Several physicochemical experiments were done to obtain further information on the conformational changes occurring in beta-conglycinin in acidic-ethanol solution, using a single molecular species of this protein, beta3. By far-UV circular dichroism (CD), a transition from beta-sheet to alpha-helical structure was observed upon addition of acidic-ethanol, and the alpha-helix content was found to reach 76% in 70% ethanol (pH 2). From analyses of near-UV CD and difference absorption spectra, it was found that the tertiary structure of the beta3 species was significantly altered at ethanol concentrations between 10 and 20%. The profiles of binding of 1-anilinonaphthalene-8-sulfonic acid to the beta3 species during acidic-ethanol denaturation were indicative of the existence of intermediate conformers in the molten globule-like denaturation state. By measuring Fourier transform infrared spectra and estimating the Stokes radius by dynamic light scattering, the beta3 molecules were found to aggregate with an increase in ethanol concentration.
Tsumura
K
K
Novelty Materials Research Institute, Tsukuba R&D Center, Fuji Oil Co., Ltd., Ibaraki, Japan. tumura@fujioil.co.jp
Enatsu
M
M
Kuramori
K
K
Morita
S
S
Kugimiya
W
W
Kuwada
M
M
Shimura
Y
Y
Hasumi
H
H
D000817:Anilino Naphthalenesulfonates; D052179:Antigens, Plant; D002942:Circular Dichroism; D000431:Ethanol; D005456:Fluorescent Dyes; D005916:Globulins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008027:Light; D010940:Plant Proteins / Q000737:chemistry*; D011487:Protein Conformation; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D012542:Scattering, Radiation; D055314:Seed Storage Proteins; D012996:Solutions; D030262:Soybean Proteins; D013025:Glycine max / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared
D000817:Anilino Naphthalenesulfonates; D052179:Antigens, Plant; D005456:Fluorescent Dyes; D005916:Globulins; D010940:Plant Proteins; D055314:Seed Storage Proteins; D012996:Solutions; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max; D000431:Ethanol; C027132:1-anilino-8-naphthalenesulfonate