The Role of Intact Oleosin for Stabilization and Function of Oleosomes

详细信息    查看全文

• 作者：Sania Maurer ; Gustav Waschatko ; Denise Schach ; Birgitta I. Zielbauer ; Jakob Dahl ; Tobias Weidner ; Mischa Bonn ; Thomas A. Vilgis
• 刊名：Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：November 7, 2013
• 年：2013
• 卷：117
• 期：44
• 页码：13872-13883
• 全文大小：486K
• 年卷期：v.117,no.44(November 7, 2013)
• ISSN：1520-5207

文摘

Lipid storage in plants is achieved among all plant species by formation of oleosomes, enclosing oil (triacylglycerides) in small subcellular droplets. Seeds are rich in this pre-emulsified oil to provide a sufficient energy reservoir for growing. The triacylglyceride core of the oleosomes is surrounded by a phospholipid monolayer containing densely packed proteins called oleosins. They are anchored in the triacylglycerides core with a hydrophobic domain, while the hydrophilic termini remain on the surface. These specialized proteins are expressed during seed development and maturation. Particularly, they play a major role in the stabilization and function of oleosomes. To better understand the importance of oleosins for oleosome stabilization, enzymatic digestion of oleosins was performed. This made it possible to compare and correlate changes in the molecular structure of oleosins and changing macroscopic properties of oleosomes. Tryptic digestion cleaves the hydrophilic part of the oleosins, which is accompanied by a loss of secondary structures as evidenced by Fourier-transform infrared and sum frequency generation spectra. After digestion, the ability of oleosins to stabilize oil鈥搘ater or air鈥搘ater interfaces was lost. The surface charge and the associated aggregation behavior of oleosomes are governed by interactions typical of proteins before digestion and by interactions typical of phospholipids after digestion.