糖基化扫描方法分析KvAP通道电压感受器S3-S4在膜中所处位置

摘要

Objective To assess the membrane localizations of S3-S4 segments in KvAP channel voltage sensor. Methods Membrane topological analysis and glycosylation scanning methods were used to assess the membrane positions. Results In KvAP channel,S3 inserts into membrane with an Ncyt/Cexo orientation and the C-terminus ends at G4 residue ;S4 inserts into membrane with an Ncyt/Cexo orientation and the N-terminus ends at G40 residue. Both of G4 and G40 residues are localized in the artificially inserted G-loop. Conclusion The C terminus of S3 and the N terminus of S4 of KvAP are localized within the membrane. Voltage sensor S3-S4 may function as non-transmembrane segments and S3 is localized in the middle of the membrane; the findings of current study are consistent with the KvAP model of voltage gating mechanism.%目的 探讨分析KvAP通道电压感受器S3-S4在膜中所处的位置.方法 采用膜拓扑结构分析和糖基化扫描方法,对KvAP通道的电压感受器S3-S4在膜中所处位置进行分析.结果 KvAP通道中,S3以Ncyt/Cexo方式插入到膜中,其C端终止于G4,S4以Ncyt/Cexo方式插入到膜中,其N端终止于G40.G4及G40均位于人工插入的G-loop中.结论 KvAP通道S3片段的C端与S4片段的N端位于膜内,电压感受器S3-S4可能为非跨膜片段,S3位于膜的中间；此结果与电压门控机制中的KvAP模型一致.