Liu Ting-hang, Chyan Chia-lin, Li Feng-yin, Tzen Jason T C
Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan
J Agric Food Chem. 2009 Mar 25;57(6):2308-13. doi: 10.1021/jf803566w.
Caleosin is a unique calcium binding protein anchoring to the surface of seed oil bodies by its central hydrophobic domain composed of an amphiphatic alpha-helix and a proline-knot subdomain. Stable artificial oil bodies were successfully constituted with recombinant caleosin overexpressed in Escherichia coli. The stability of artificial oil bodies was slightly or severely reduced when the amphiphatic alpha-helix or proline-knot subdomain in the hydrophobic domain of caleosin was truncated. Deletion of the entire central hydrophobic domain substantially increased the solubility of the recombinant caleosin, leading to a complete loss of its capability to stabilize these oil bodies. A recombinant protein engineered with the hydrophobic domain of caleosin replaced by that of oleosin, the abundant structural protein of seed oil bodies, could stabilize the artificial oil bodies, in terms of thermo- and structural stability, as effectively as caleosin or oleosin.
钙结合蛋白是一种独特的钙结合蛋白，通过其由两亲性α-螺旋和脯氨酸结亚结构域组成的中央疏水结构域锚定在种子油体表面。利用在大肠杆菌中过表达的重组钙结合蛋白成功构建了稳定的人工油体。当钙结合蛋白疏水结构域中的两亲性α-螺旋或脯氨酸结亚结构域被截短时，人工油体的稳定性会轻微或严重降低。删除整个中央疏水结构域会显著提高重组钙结合蛋白的溶解度，导致其稳定这些油体的能力完全丧失。用种子油体中丰富的结构蛋白油质蛋白的疏水结构域替换钙结合蛋白的疏水结构域构建的重组蛋白，在热稳定性和结构稳定性方面，能像钙结合蛋白或油质蛋白一样有效地稳定人工油体。
