Abstract
Non-specific lipid transfer protein(ns-LTP) purfied form rice is a highly basic protein with molecular weight about 9 kDa. The function of ns-LTP has been proposed to be able to transfer lipid between membranes. The structure of ns-LTP is simply composed of four a-helices and a long-chain C-terminal tail. The four a-helices are connected each other through flexible loop and four conserved-disulfide bonds. The protein bears a hydrophobic cavity running through the whole molecule that was proposed to be a phospholipid binding site. Owing to its structure has a hydrophobic cavity and four conserved-disulfide bonds, a study of the folding of ns-LTP is therefore made to understand the folding mechanism. In this thesis, circular dichroism(CD)，fluorometer，stopped-flow CD and 1H/D exchange methods were adopted to study the folding of ns-LTP. First, the different conditions such as pH，temperature and chemical denaturant were used to trace the stability of ns-LTP. Based on the results obtained from CD and fluorometer, pH7 and guanidine hydrochloride were selected for further understanding the mechanism of folding. Then, investigation of the kinetics of ns-LTP folding was proceeded by stopped-flow CD. The result shows the folding of ns-LTP was complete wthin 0.5 sec. Due to the observation of intermediate state in the refolding pathway, the whole kinetic is concluded to not be a two-state mechanism. Finally, the result of 1H/D exchange experiment shows that the forth a-helix of ns-LTP is the most stable region.