Solution structure of the N-terminal amphitropic domain of Escherichia coli glucose-specific enzyme IIA in membrane-mimetic micelles.
Solution structure of the N-terminal amphitropic domain of Escherichia coli glucose-specific enzyme IIA in membrane-mimetic micelles.
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膜模拟胶束中大肠杆菌葡萄糖特异性酶 IIA 的 N 端两亲性结构域的溶液结构。
DOI：
10.1110/ps.0301503
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Peterkofsky,Alan
中科院分区：
文献类型：
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作者：
Wang,Guangshun;Keifer,PaulA;Peterkofsky,Alan
大肠杆菌磷酸烯醇丙酮酸：糖磷酸转移酶系统的酶 IIAGlc 的 N 末端结构域赋予蛋白质两向性，允许 IIAGlc 在细胞质和膜之间穿梭。为了进一步了解这种两亲性蛋白质，我们通过核磁共振波谱阐明了与 IIAGlc N 端结构域相对应的合成肽的溶液结构。在水中，这种肽主要是无序的，与之前在没有膜的情况下获得的数据一致。然而，在二己酰磷脂酰甘油 (DHPG) 或十二烷基硫酸钠 (SDS) 的洗涤剂胶束中，肽的残基 Phe 3-Val 10 在基于 NOE 衍生距离限制计算的结构整体中采用螺旋构象。叠加螺旋区域主链原子的均方根偏差在 DHPG 中为 0.18 Å，在 SDS 中为 0.22 Å。结构、化学位移和自旋-自旋耦合常数都表明，在 IIAGlc N 端结构域的 4 个赖氨酸中，只有两亲性螺旋区域的 Lys 5 和 Lys 7 与 DHPG 相互作用。此外，还使用分子间 NOESY 实验研究了肽-去垢剂相互作用。阴离子去污剂 DHPG、SDS 和 2,2-二甲基-2-硅戊烷-5-磺酸钠盐 (DSS) 的脂肪链均显示出与肽的分子间 NOE 交叉峰，为 IIAGlcin 与模拟膜胶束结合的假定膜锚定提供了直接证据。
The N‐terminal domain of enzyme IIAGlcof theEscherichia coliphosphoenolpyruvate:sugar phosphotransferase system confers amphitropism to the protein, allowing IIAGlcto shuttle between the cytoplasm and the membrane. To further understand this amphitropic protein, we have elucidated, by NMR spectroscopy, the solution structure of a synthetic peptide corresponding to the N‐terminal domain of IIAGlc. In water, this peptide is predominantly disordered, consistent with previous data obtained in the absence of membranes. In detergent micelles of dihexanoylphosphatidylglycerol (DHPG) or sodium dodecylsulfate (SDS), however, residues Phe 3–Val 10 of the peptide adopt a helical conformation in the ensemble of structures calculated on the basis of NOE‐derived distance restraints. The root mean square deviations for superimposing the backbone atoms of the helical region are 0.18 Å in DHPG and 0.22 Å in SDS. The structure, chemical shifts, and spin–spin coupling constants all indicate that, of the four lysines in the N‐terminal domain of IIAGlc, only Lys 5 and Lys 7 in the amphipathic helical region interact with DHPG. In addition, the peptide‐detergent interactions were investigated using intermolecular NOESY experiments. The aliphatic chains of anionic detergents DHPG, SDS, and 2,2‐dimethyl‐2‐silapentane‐5‐sulfonate sodium salt (DSS) all showed intermolecular NOE cross‐peaks to the peptide, providing direct evidence for the putative membrane anchor of IIAGlcin binding to the membrane‐mimicking micelles.