FRUCTANS INTERACT STRONGLY WITH MODEL MEMBRANES

Bacterial fructans with a high degree of polymerisation cause a very l arge increase in surface pressure of lipid monolayers at the air-water interface with a broad range of lipids, including phosphatidylethanol amine and several types of phosphatidylcholines. The surface active ef fect of fructans contrasts strongly with the maximal effects observed for trehalose, sucrose and glucose under comparable conditions (20 and 0.6 mN/m for fructans and the other sugars, respectively). The result s demonstrate a profound and specific membrane interaction of the fruc tans which is probably very different from the effect of the smaller c arbohydrates. The fructan concentrations used in this study are within the physiological range observed in fructan-accumulating plants. The suggested water-stress protective effect of fructans may be induced by membrane-fructan interaction which prevent lipid condensation and pha se transitions to take place. (C) 1998 Elsevier Science B.V. All right s reserved.