摘要
固醇敏感多肽区 (SSD)在胆固醇自我平衡调节、物质运输以及细胞信号转导中发挥重要的作用 .通过对三界系统中 ,不同门纲代表种 (2 2个种 )的 SSD序列分析发现 ,SSD在组成上有很大的偏向性 ,在三级结构上高度保守 .分子系统树的结果表明 SSD明显分为 PTC、NPC1、Ptr、SCAP、Disp、HMGCR和原核生物类 7大分枝 ,功能相关基因的 SSD并不聚集在一起 ,说明 SSD在进化中受到的选择压力是不同的 .推测是一种原始的拥有编码 SSD跨膜结构域序列通过交换转移和其他的编码序列组成新的基因 ,再逐步进化形成固定的功能 ,而 SSD保持了与运输有关的功能 .进一步证实了 Ref[13]提出的 Hh- PTC- Sm o信号系统作用模型 .
The Sterol-sensing domain plays an important role in cholesterol homeostasis, cholesterol transport and cholesterol-linked signalling. We analyzed the 22 sequences of SSD from representative species of different phyla. The results show that the amino acid composition of SSD is biased greatly but three-dimensional structure is conservative. Molecular phylogenetic analyses identified seven main clusters as PTC,NPC1,Ptr,SCAP,Disp,HMGCR and prokaryote-related genes. But the function-linked proteins were not closely classified,which suggested that the selective pressure of SSD in different proteins was different. We concluded one primary sequence harboring the SSD-like sequence formed new proteins with other coding sequences through exchanging or transferring,then evolved into fixed functions, but all SSD preserved the transporting functions. Our results confirm the Ref13′s new model of Hh-PTC-Smo signal pathway.
出处
《河南师范大学学报（自然科学版）》
CAS
CSCD
2003年第1期88-92,109,共6页
Journal of Henan Normal University(Natural Science Edition)
