Le Guernevé C, Seigneuret M, Marion D
IPV, INRA, 2 place Viala, Montpellier, 34060, France.
Arch Biochem Biophys. 1998 Dec 15;360(2):179-86. doi: 10.1006/abbi.1998.0931.
Puroindoline-a is the main component of a new family of proteins that has been suggested to exert an antimicrobial activity in plant seeds through an interaction with lipid membranes. Here the interaction of puroindoline-a with model phospholipid membranes and micelles has been studied using intrinsic tryptophan fluorescence, fluorescence polarization of diphenyl hexatriene, and proteolysis experiments. The protein appears to interact with both zwitterionic and negative phospholipids. The interaction with phosphatidylcholine is characterized by low-affinity surface binding with very limited penetration into the hydrophobic membrane interior. On the other hand, the interaction with phosphatidylglycerol displays a high affinity and involves a partial penetration of the protein into the bilayer interior that disrupts acyl chain packing. The specificity appears to be due to the presence of a stretch of positively charged residues in the protein sequence. In all, the lipid-binding properties of puroindoline-a resemble those of cardiotoxins, another family of proteins for which a disruptive effect on the membrane structure has been involved to explain their biological function.
麦类吲哚蛋白-a是一类新蛋白质家族的主要成分，有人认为该蛋白通过与脂质膜相互作用在植物种子中发挥抗菌活性。本文利用色氨酸固有荧光、二苯基己三烯荧光偏振和蛋白水解实验研究了麦类吲哚蛋白-a与模型磷脂膜和胶束的相互作用。该蛋白似乎能与两性离子磷脂和负电荷磷脂相互作用。与磷脂酰胆碱的相互作用表现为低亲和力的表面结合，且对疏水膜内部的穿透非常有限。另一方面，与磷脂酰甘油的相互作用显示出高亲和力，且该蛋白会部分穿透双层内部，从而破坏酰基链堆积。这种特异性似乎是由于该蛋白序列中存在一段带正电荷的残基。总之，麦类吲哚蛋白-a的脂质结合特性类似于心脏毒素，心脏毒素是另一类蛋白质家族，对其膜结构的破坏作用已被用于解释其生物学功能。
