Maezawa S, Yoshimura T
Institute for Enzyme Research, University of Tokushima, Japan.
Biochem Biophys Res Commun. 1990 Nov 30;173(1):134-40. doi: 10.1016/s0006-291x(05)81032-0.
Below pH6, clathrin induces fusion of liposomes containing phosphatidylserine (PS) [Maezawa et al. (1989) Biochemistry 28, 1422-1428]. Under similar conditions clathrin forms self-aggregates, suggesting that the associated form of clathrin may be involved in the fusion process. For examination of this possibility, the extent of fluorescence energy transfer from N-(p-(2-benzimidazolyl)phenyl)maleimide (BIPM)-labeled clathrin to N-(7-dimethyl-amino-4-methyl-3-coumarinyl)maleimide (DACM)-labeled clathrin in the presence of liposomes and the number of binding sites for clathrin in one liposome were examined in the pH region inducing membrane fusion. A high degree of transfer was observed, and the area on the membrane surface occupied by a clathrin molecule was estimated to be much less than that expected from its size, indicating that clathrin binds to the liposome membrane as an associated form, which may be essential for induction of membrane fusion.
在pH值低于6时，网格蛋白可诱导含磷脂酰丝氨酸（PS）的脂质体融合[前泽等人（1989年），《生物化学》28卷，第1422 - 1428页]。在类似条件下，网格蛋白会形成自我聚集体，这表明网格蛋白的缔合形式可能参与了融合过程。为了验证这种可能性，在诱导膜融合的pH范围内，检测了在脂质体存在的情况下，从N-（对-（2-苯并咪唑基）苯基）马来酰亚胺（BIPM）标记的网格蛋白到N-（7-二甲基氨基-4-甲基-3-香豆素基）马来酰亚胺（DACM）标记的网格蛋白的荧光能量转移程度，以及一个脂质体中网格蛋白的结合位点数。观察到了高度的能量转移，并且估计膜表面上一个网格蛋白分子占据的面积远小于根据其大小预期的面积，这表明网格蛋白以缔合形式结合到脂质体膜上，这可能是诱导膜融合所必需的。
