Horniak L, Pilon M, van 't Hof R, de Kruijff B
Institute of Molecular and Subcellular Biology, Comenius University, Bratislava, Slovakia.
FEBS Lett. 1993 Nov 15;334(2):241-6. doi: 10.1016/0014-5793(93)81720-k.
Import of proteins into chloroplasts depends on an N-terminal transit sequence. Transit sequences contain little primary sequence similarity and therefore recognition of these sequences is thought to involve specific folding. To assess the conformational flexibility of the transit sequence, we studied the transit peptide of preferredoxin (trfd) by circular dichroism. In buffer, trfd is in a random coil conformation. A large increase in alpha-helix was induced in the presence of micelles or vesicles formed by anionic lipids. Less pronounced changes in secondary structure were induced by zwitterionic detergents but no changes were observed in the presence of neutral detergents or vesicles composed of phosphatidylcholine.
蛋白质导入叶绿体依赖于N端转运序列。转运序列的一级序列相似性很低，因此这些序列的识别被认为涉及特定的折叠。为了评估转运序列的构象灵活性，我们通过圆二色性研究了嗜光素（trfd）的转运肽。在缓冲液中，trfd呈无规卷曲构象。在由阴离子脂质形成的胶束或囊泡存在下，α-螺旋大幅增加。两性离子去污剂诱导的二级结构变化不太明显，但在中性去污剂或由磷脂酰胆碱组成的囊泡存在下未观察到变化。
