tailieunhanh - Báo cáo khoa học: The thermodynamic analysis of protein stabilization by sucrose and glycerol against pressure-induced unfolding The typical example of the 33-kDa protein from spinach photosystem II

We have studied the reaction native«denatured for the 33-kDa protein isolated from photosystem II. Sucrose and glycerol have profound effects on pressure-induced unfolding. The additives shift the equilibrium to the left; they also cause a significant decrease in the standard volume change (DV). The change in DVwas related to the sucrose and glycerol concentrations. | Eur. J. Biochem. 270 1654-1661 2003 FEBS 2003 doi The thermodynamic analysis of protein stabilization by sucrose and glycerol against pressure-induced unfolding The typical example of the 33-kDa protein from spinach photosystem II Kanachena Ruan1. Chunhe Xu2. Tinatina Li1. Jiona Li1. Reinhard Lanae3 and Claude Balnv3 1Laboratory of Proteomics Institute of Biochemistry and Cell Biology Shanghai Institute for Biological Science Chinese Academy of Sciences Shanghai China 2Institute of Plant Physiology Shanghai Institute for Biological Science Chinese Academy of Sciences Shanghai China 3Institut National de la Sante et de la Recherche Medicale INSERM U 128 IFR 24 CNRS Montpellier France We have studied the reaction native denatured for the 33-kDa protein isolated from photosystem II. Sucrose and glycerol have profound effects on pressure-induced unfolding. The additives shift the equilibrium to the left they also cause a significant decrease in the standard volume change AT . The change in AV was related to the sucrose and glycerol concentrations. The decrease in AV varied with the additive sucrose caused the largest effect glycerol the smallest. The theoretical shift of the half-unfolding pressure P1 2 calculated from the net increase in free energy by addition of sucrose and glycerol was lower than that obtained from experimental measurements. This indicates that the free energy change caused by preferential hydration of the protein is not the unique factor involved in the protein stabilization. The reduction in AV showed a large contribution to the theoretical P1 2 shift suggesting that the AV change caused by the sucrose or glycerol was associated with the protein stabilization. The origin of the AV change is discussed. The rate of pressure-induced unfolding in the presence of sucrose or glycerol was slower than the refolding rate although both were significantly slower than that observed without any stabilizers. Keywords .