Myelin proteolipid protein-induced aggregation of lipid vesicles: efficacy of the various molecular species.
Myelin proteolipid protein-induced aggregation of lipid vesicles: efficacy of the various molecular species.
复制标题
髓鞘蛋白脂质蛋白诱导的脂质囊泡聚集：各种分子种类的功效。
DOI：
10.1023/a:1021659313213
复制
发表时间：
2002
影响因子：
4.4
通讯作者：
Howard,TamaraA
中科院分区：
文献类型：
--
作者：
Bizzozero,OscarA;Howard,TamaraA
The different molecular species that form the myelin proteolipid protein family were isolated by size-exclusion and ion-exchange chromatography in organic solvents and their adhesive properties were tested using a vesicle aggregation assay. Addition of the major proteolipid (PLP) to phosphatidylcholine-cholesterol vesicles caused their clustering as determined by increase in O.D.450 nmand by transmission electron microscopy. A small fraction of the aggregated vesicles underwent fusion as determined by resonance energy transfer experiments. Vesicle aggregation by PLP, but not the dissociation of the aggregates, was influenced by pH suggesting that electrostatic interactions are important only during cluster formation. Cleavage of disulfide bonds and methylation of carboxyl groups in PLP greatly reduced the aggregating activity, indicating that the process is dependent on the protein's conformation. Unexpectedly, the proteolipid DM-20 was also effective at inducing the clustering of neutral lipid vesicles. In contrast, three protein fractions comprising the naturally-occurring PLP fragments 1-107/112, 113/125-276 and 129/131-276, bearing different net charges, displayed a much lower activity. In addition, trypsin digestion of PLP resulted in a progressive decrease in the protein's ability to induce vesicle aggregation which coincided with the disappearance of the full-length molecule. Together, these results suggest that even large PLP fragments cannot fulfill the adhesive function of the intact protein.
