The Effect of Globular Protein from Aleurone Cells of Barley on Stearic Acid Monolayers

Aleurone cells of barley accumulate the major storage globular protein, which is deposited in different patterns, such as protein and lipid self-assemblies. To better understand the complexity of storage self-assemblies, a fatty acid is chosen as a lipid model, namely stearic acid, SA, because of its high stability in monolayers at the air/aqueous solutions interface. The effect of aleurone cell protein, AC protein, on the phase behavior and surface structure of SA monolayers at the air/water interface has been studied by a combined Langmuir and Langmuir-Blodgett (LB) technique and by atomic force microscopy (AFM) investigation. The AC protein and SA monolayers were transferred on glass support, at several controlled surface pressures, characteristic for both the condensed liquid and solid phase of pure SA monolayers. The results indicate that globular particles of AC protein adsorb on and penetrate into and specifically interact with SA monolayers stabilizing the lipid/protein interface by achieving highly ordered self-assemblies, which may also occur within aleurone layers. These structures might play an important role both in aleurone cell development and in seedling growth.