The 1.8‐Å X‐ray structure of the Escherichia coli PotD protein complexed with spermidine and the mechanism of polyamine binding
The 1.8‐Å X‐ray structure of the Escherichia coli PotD protein complexed with spermidine and the mechanism of polyamine binding
复制标题
大肠杆菌PotD蛋白与亚精胺复合的1.8Å X射线结构及多胺结合机制
作者：
S. Sugiyama;Y. Matsuo;D. Vassylyev;M. Matsushima;K. Morikawa;K. Maenaka;K. Kashiwagi;K. Igarashi
来自大肠杆菌的PotD蛋白是存在于周质中的多胺转运系统的组分之一。该组分特异性结合亚精胺或腐胺。对E.与亚精胺复合的大肠杆菌PotD蛋白在1.8 μ m分辨率下溶解，并揭示了详细的底物结合机制。该结构提供了结合的亚精胺的详细构象。此外，在氨基末端结构域和羧基末端结构域之间的结合位点中清楚地鉴定出水分子。通过这个水分子，结合的亚精胺分子与Thr 35和Ser 211形成两个氢键。多胺转运的另一个周质组分PotF蛋白与PotD蛋白具有35%的序列同一性，并且它仅结合腐胺，而不结合亚精胺。为了理解这些不同的底物特异性，在PotD晶体结构的基础上进行了PotF蛋白的模型构建。假设的结构表明，在PotF的赖氨酸349的侧链抑制亚精胺的结合，因为它的正电荷和亚精胺之间的排斥力。另一方面，腐胺可以被容纳到结合位点没有任何空间位阻，因为它的分子大小比亚精胺小得多，并且带正电荷的氨基相对远离赖氨酸349。
The PotD protein from Escherichia coli is one of the components of the polyamine transport system present in the periplasm. This component specifically binds either spermidine or putrescine. The crystal structure of the E. coli PotD protein complexed with spermidine was solved at 1.8 Å resolution and revealed the detailed substrate‐binding mechanism. The structure provided the detailed conformation of the bound spermidine. Furthermore, a water molecule was clearly identified in the binding site lying between the amino‐terminal domain and carboxyl‐terminal domain. Through this water molecule, the bound spermidine molecule forms two hydrogen bonds with Thr 35 and Ser 211. Another periplasmic component of polyamine transport, the PotF protein, exhibits 35% sequence identity with the PotD protein, and it binds only putrescine, not spermidine. To understand these different substrate specificities, model building of the PotF protein was performed on the basis of the PotD crystal structure. The hypothetical structure suggests that the side chain of Lys 349 in PotF inhibits spermidine binding because of the repulsive forces between its positive charge and spermidine. On the other hand, putrescine could be accommodated into the binding site without any steric hindrance because its molecular size is much smaller than that of spermidine, and the positively charged amino group is relatively distant from Lys 349.
登录
查看更多内容
图 2 参与鼠伤寒沙门氏菌主动转运的硫酸盐结合蛋白的解析结构。
影响因子：
5.6
作者：
Pflugrath,JW;Quiocho,FA
通讯作者：
Quiocho,FA
影响因子：
5.6
作者：
J. Sack;M. Saper;F. Quiocho
通讯作者：
J. Sack;M. Saper;F. Quiocho
影响因子：
11.2
作者：
Anthony E. Pegg
通讯作者：
Anthony E. Pegg
鼠伤寒沙门氏菌赖氨酸、精氨酸、鸟氨酸结合蛋白 (LAO) 的晶体结构，分辨率为 2.7-A。
DOI：
--
发表时间：
1991
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Kang,CH;Shin,WC;Yamagata,Y;Gokcen,S;Ames,GF;Kim,SH
通讯作者：
Kim,SH
以 2.4 A 分辨率精修的 L-亮氨酸结合蛋白结构以及与 Leu/Ile/Val 结合蛋白结构的比较。
影响因子：
5.6
作者：
Sack,JS;Trakhanov,SD;Tsigannik,IH;Quiocho,FA
通讯作者：
Quiocho,FA