Evidence for two distinct conformations of the Escherichia coli mannitol permease that are important for its transport and phosphorylation functions
Evidence for two distinct conformations of the Escherichia coli mannitol permease that are important for its transport and phosphorylation functions
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大肠杆菌甘露醇渗透酶的两种不同构象对其转运和磷酸化功能很重要的证据
DOI：
--
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发表时间：
1989
影响因子：
4
通讯作者：
G. Jacobson
中科院分区：
文献类型：
--
作者：
S. Khandekar;G. Jacobson
在脱氧胆酸存在下，大肠杆菌甘露醇渗透酶（甘露醇特异性酶II）的柱层析显示，活性渗透酶可以存在于至少两种结合状态，其表观分子量与单体和二聚体一致。甘露醇的存在和磷酸烯醇丙酮酸（PEP）依赖的蛋白磷酸化有利于单体构象。二聚体由无机磷酸盐（Pi）稳定，这也刺激甘露醇和甘露醇1 -磷酸之间的磷酸交换（甘露醇整体依赖PEP磷酸化的部分反应）。磷交换反应的动力学分析表明，Pi通过增加反应的Vmax来促进磷交换。建立了甘露醇渗透酶两种构象的动力学模型。假设单体（或二聚体的不太稳定的构象）参与了最初的甘露醇结合和PEP依赖的磷酸化步骤，而稳定相关的二聚体被认为参与了随后的步骤，包括渗透酶、甘露醇和甘露醇1 -磷酸之间的直接磷酸转移。
Column chromatography of the Escherichia coli mannitol permease (mannitolspecific enzyme II of the phosphotransferase system) in the presence of deoxycholate has revealed that the active permease can exist in at least two association states with apparent molecular weights consistent with a monomer and a dimer. The monomeric conformation is favored by the presence of mannitol and by the phosphoenolpyruvate (PEP)‐dependent phosphorylation of the protein. The dimer is stabilized by inorganic phosphate (Pi), which also stimulates phospho‐exchange between mannitol and mannitol 1‐phosphate (a partial reaction in the overall PEP‐dependent phosphorylation of mannitol). Kinetic analysis of the phospho‐exchange reaction revealed that Pi stimulates phospho‐exchange by increasing the Vmax of the reaction. A kinetic model for mannitol permease function is presented involving both conformations of the permease. The monomer (or a less‐stable conformation of the dimer) is hypothesized to be involved in the initial mannitol‐binding and PEP‐dependent phosphorylation steps, while the stably associated dimer is suggested to participate in later steps involving direct phosphotransfer between the permease, mannitol and mannitol 1‐phosphate.
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细菌磷酸转移酶系统的甘露醇特异性酶 II。
DOI：
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发表时间：
1983
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Jacobson,GR;Lee,CA;Leonard,JE;SaierJr,MH
通讯作者：
SaierJr,MH
大肠杆菌甘露醇渗透酶的亚基相互作用：与酶活性的相关性。
影响因子：
2.9
作者：
Stephan,MM;Jacobson,GR
通讯作者：
Jacobson,GR
大肠杆菌甘露醇渗透酶的膜处置：膜结合域和细胞质域的鉴定。
影响因子：
2.9
作者：
Stephan,MM;Jacobson,GR
通讯作者：
Jacobson,GR
与细菌磷酸转移酶系统的酶 II 相关的催化活性。
DOI：
10.1002/jss.400140303
发表时间：
1980
期刊：
Journal of supramolecular structure
影响因子：
--
作者：
SaierJr,MH
通讯作者：
SaierJr,MH