TITLE:
Secondary Structure Changes and Thermal Stability of Plasma Membrane Proteins of Wheat Roots in Heat Stress
AUTHORS:
Xin Zhao, Yong Shi, Li Chen, Fenlin Sheng, Haiyan Zhou
KEYWORDS:
Plasma Membrane, Heat Stress, Protein Second Structure, ATR-FTIR
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.2 No.6,
December
30,
2011
ABSTRACT: The wheat roots membrane separates the cell from the environment around it and encloses the cell contents. The pro-tein secondary structure and thermal stability of the plasma membrane of wheat root have been characterized in D2O buffer from 20°C to 90°C by Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Quantitative analysis of the amide I band (1700 - 1600 cm–1) showed that the plasma membrane proteins contains 41% α-helix, 16% β-sheet, 18% turn, and 25% disorder structures at 20°C. At elevated temperatures from 25°C up to 90°C, the α-helix and the β-sheet structure unfold into turns and the disorder structure, with a major conformational transition occurring at 50°C. There is a rapid decline in H+-ATPase activity of plasma membrane from 35°C to 55°C and it remain very low level H+-ATPase activity of PM from 55°C to 90°C. Therefore the protein conformational transition was one of reasons of loses H+-ATPase activity of plasma membrane.