Signal recognition particle 信号识别颗粒SRP Signal recognition particle是由7 S Snrna和 proteins组成的rRNP,能够识别信号肽序列 SRP结合于内质网膜外侧的受体上,此受体称 为停靠蛋白 docking protein 蛋白质分子在穿过内质网腔时,信号肽被信号 肽酶 signal peptidase切除。 在 Golgi裝置内,蛋白质分子被修饰,通常为糖 基化修饰。不同的糖基化修饰可能控制着蛋白 质的最终定位
Signal recognition particle 信号识别颗粒SRP • Signal recognition particle 是由7S snRNA和 proteins组成的rRNP，能够识别信号肽序列 • SRP结合于内质网膜外侧的受体上，此受体称 为停靠蛋白docking protein。 • 蛋白质分子在穿过内质网腔时，信号肽被信号 肽酶signal peptidase切除。 • 在Golgi装置内，蛋白质分子被修饰，通常为糖 基化修饰。不同的糖基化修饰可能控制着蛋白 质的最终定位
The structure of srp Alu RNA domain s rna domain SRP9/14 SRP68/72 SRP54 53 SRP19 Elongation arrest Receptor binding Signal recogntion The 7S RNA of the srP particle is divided into two parts. The 100 bases at the 5 end and 45 bases at the 3 end are closely related to the sequence ofalu RNA. a common mammalian smalI RNA. They therefore define the aLl domain. The remaining part of the RNA comprises the S domain. Five of the six proteins bind directly to the 7S RNA. each function of the srp is associated with a particular protein(s)
The structure of SRP The 7S RNA of the SRP particle is divided into two parts. The 100 bases at the 5 end and 45 bases at the 3 end are closely related to the sequence of ALU RNA, a common mammalian small RNA. They therefore define the ALU domain. The remaining part of the RNA comprises the S domain. Five of the six proteins bind directly to the 7S RNA. Each function of the SRP is associated with a particular protein(s)
● Signal for Protein transported into outer membrane mitochondria and chloroplas TOM receptor 前导肽通常是疏水的,约2m,由[亚 非电负性氨基酸构成,中间夹有碱 性氨基酸,而没有酸性氨基酸,羟 Mat i tuner 基氨基酸含量 Inner mem 易形成双亲α螺旋轮 amphiphilic Intemem brane space Outer membrane helix 不同的前导肽缺乏同源性,这意味 interrmem brane space 着和识别有关的信号不是一极结构 而是二级或三级结构 在细胞器的内外膜上都发现前导肽 的受体 前导肽的切除是由导肽酶 transit peptidase完成的
Protein transported into mitochondria and chloroplasts • 前导肽通常是疏水的，约20aa，由 非电负性氨基酸构成，中间夹有碱 性氨基酸，而没有酸性氨基酸，羟 基氨基酸含量高 • 易形成双亲螺旋轮amphiphilic helix • 不同的前导肽缺乏同源性，这意味 着和识别有关的信号不是一极结构， 而是二级或三级结构 • 在细胞器的内外膜上都发现前导肽 的受体 • 前导肽的切除是由导肽酶transit peptidase完成的
Two kinds of signal The leader of yeast Initiation cytochrome cl contains an N-terminal region Charged leader region for mitochondrial targeting that targets the protein k阿四匣四网回园回 to the mitochondrion followed by a region m四回p回四四圆四 that targets the(cleaved) Cleavage 1 protein to the inner membrane. The leader回四剛回四回國画回回回 is removed by two Continuous uncharged leader region targets inner membrane cleavage events Cleavage 2
Two kinds of signal • The leader of yeast cytochrome c1 contains an N-terminal region that targets the protein to the mitochondrion, followed by a region that targets the (cleaved) protein to the inner membrane. The leader is removed by two cleavage events
螺旋轮 Met] Thr l L Leu18X 2 L Ser i Se Th ·酵母细胞色素氧化酶C亚基先导肽形成的两亲螺旋结构
螺旋轮 • 酵母细胞色素氧化酶C亚基先导肽形成的两亲螺旋结构