Conformational study of globulin from rice (Oryza sativa) seeds by Fourier-transform infrared spectroscopy.
The conformation of rice globulin (10%, w/v, in deuterated phosphate buffer, pD 7.4) under the influence of pH, chaotropic salts, several protein structure perturbants and heat treatments was studied by Fourier-transform infrared (FTIR) spectroscopy. Rice globulin exhibited seven major bands in the region of 1700-1600 cm-1 and the spectrum suggests high alpha-helical content with large quantities of beta-sheet and beta-turn structures. Highly acidic and alkaline pH conditions induced changes in band intensity attributed to intermolecular beta-sheet structure (1681 and 1619 cm-1). Addition of chaotropic salts led to progressive changes in band intensity, following the lyotropic series of anions, whereas several protein structure perturbants caused shifts in band positions. Heating at increasing temperature led to progressive decreases in alpha-helical content and increases in random coil structures, suggesting protein denaturation. This was accompanied by intensity increases in the intermolecular beta-sheet transitions.
Ellepola
Sureka Weerakoon
SW
The University of Hong Kong, Department of Botany, Kadoorie, Hong Kong, China.
Choi
Siu Mei
SM
Ma
Ching Yung
CY
D005916:Globulins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D012275:Oryza; D010710:Phosphates / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry*; D011487:Protein Conformation; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D012492:Salts / Q000494:pharmacology; D012639:Seeds / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013696:Temperature
D005916:Globulins; D010710:Phosphates; D010940:Plant Proteins; D012492:Salts