An amphiphilic region in the cytoplasmic domain of KdpD is recognized by the signal recognition particle and targeted to the Escherichia coli membrane
An amphiphilic region in the cytoplasmic domain of KdpD is recognized by the signal recognition particle and targeted to the Escherichia coli membrane
复制标题
KdpD 胞质结构域中的两亲性区域被信号识别颗粒识别并靶向大肠杆菌膜
作者：
Katja S Maier;Stefanie Hubich;Helga Liebhart;S. Krauss;A. Kuhn;S. Facey
大肠杆菌的传感蛋白KdpD由一个大的N端亲水区（aa 1-400）、四个跨膜区（aa 401-498）和一个大的C端亲水区（aa 499-894）组成。KdpD需要信号识别颗粒（SRP）用于其靶向膜。KdpD内的缺失表明，前50个残基是SRP驱动的膜插入所需的。只有当SRP存在时，才发现绿色荧光蛋白（GFP）与KdpD的融合蛋白定位于膜上。当前50个KdpD残基缺失时，没有观察到GFP的膜靶向。仅含有与GFP融合的前25个氨基酸的KdpD的截短突变体失去了与SRP特异性相互作用的能力，而SRP与GFP融合的KdpD的前48个氨基酸之间的特异性相互作用通过下拉实验证实。总之，在KdpD的氨基末端结构域内的27个残基的小的两亲性区域（aa 22-48）被SRP识别并将蛋白质靶向至膜。这表明在细胞质中具有大的N末端区域的膜蛋白可以在早期被膜靶向，以允许其远端跨膜区域的共翻译膜插入。
The sensor protein KdpD of Escherichia coli is composed of a large N‐terminal hydrophilic region (aa 1–400), four transmembrane regions (aa 401–498) and a large hydrophilic region (aa 499–894) at the C‐terminus. KdpD requires the signal recognition particle (SRP) for its targeting to the membrane. Deletions within KdpD show that the first 50 residues are required for SRP‐driven membrane insertion. A fusion protein of the green fluorescent protein (GFP) with KdpD is found localized at the membrane only when SRP is present. The membrane targeting of GFP was not observed when the first 50 KdpD residues were deleted. A truncated mutant of KdpD containing only the first 25 amino acids fused to GFP lost its ability to specifically interact with SRP, whereas a specific interaction between SRP and the first 48 amino acids of KdpD fused to GFP was confirmed by pull‐down experiments. Conclusively, a small amphiphilic region of 27 residues within the amino‐terminal domain of KdpD (aa 22–48) is recognized by SRP and targets the protein to the membrane. This shows that membrane proteins with a large N‐terminal region in the cytoplasm can be membrane‐targeted early on to allow co‐translational membrane insertion of their distant transmembrane regions.
影响因子：
3.5
作者：
Cormack, BP;Valdivia, RH;Falkow, S
通讯作者：
Falkow, S
DOI：
10.1073/pnas.82.4.1074
发表时间：
1985-01-01
影响因子：
11.1
作者：
TABOR, S;RICHARDSON, CC
通讯作者：
RICHARDSON, CC
影响因子：
5.6
作者：
Weiche, Benjamin;Buerk, Jonas;Koch, Hans-Georg
通讯作者：
Koch, Hans-Georg