Membrane-induced alteration of the secondary structure in the SWAP-70 pleckstrin homology domain.
Membrane-induced alteration of the secondary structure in the SWAP-70 pleckstrin homology domain.
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DOI：
10.1093/jb/mvr146
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发表时间：
2012-04
影响因子：
2.7
通讯作者：
N. Tokuda;K. Kawai;Young-Ho Lee;T. Ikegami;S. Yamaguchi;H. Yagisawa;Y. Fukui;S. Tuzi
中科院分区：
文献类型：
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作者：
N. Tokuda;K. Kawai;Young-Ho Lee;T. Ikegami;S. Yamaguchi;H. Yagisawa;Y. Fukui;S. Tuzi
使用CD，荧光和NMR光谱法研究了开关相关蛋白-70（SWAP-70）在溶液中和脂质双层膜表面的普列克底物蛋白同源（PH）结构域构象的差异。SWAP-70在细胞内从细胞质到质膜再到细胞核的再定位与其细胞功能有关。SWAP-70的PH结构域包含磷酸肌醇结合位点和核定位信号，其分别将SWAP-70定位于质膜和核。CD和荧光光谱表明，一个显着的构象变化，涉及形成无序结构发生时，PH结构域结合D-肌磷脂酰肌醇3，4，5-三磷酸或D-肌磷脂酰肌醇4，5-二磷酸包埋在脂质双层囊泡。NMR谱表明，PH结构域C-末端α-螺旋的Ala和Trp残基发生构象变化，在囊泡表面形成无序结构。这些构象的改变并没有引起协会与肌醇1，3，4，5-tetrakisphosphate在溶液中或共存的磷脂酰胆碱囊泡。PH结构域的C-末端α-螺旋的解折叠需要通过与磷酸肌醇缔合与脂质双层平面的相互作用。SWAP-70 C端α-螺旋的解旋可以调节SWAP-70在质膜表面的功能。
Differences in the conformation of the pleckstrin homology (PH) domain of switch-associated protein-70 (SWAP-70) in solution and at the lipid bilayer membrane surface were examined using CD, fluorescence and NMR spectroscopy. Intracellular relocalization of SWAP-70 from the cytoplasm to the plasma membrane and then to the nucleus is associated with its cellular functions. The PH domain of SWAP-70 contains a phosphoinositide-binding site and a nuclear localization signal, which localize SWAP-70 to the plasma membrane and nucleus, respectively. CD and fluorescence spectra showed that a significant conformational alteration involving formation of disordered structure occurs when the PH domain binds to D-myo-phosphatidylinositol 3,4,5-trisphosphate or D-myo-phosphatidylinositol 4,5-bisphosphate embedded in lipid bilayer vesicles. NMR spectra indicate that Ala and Trp residues located in the C-terminal α-helix of the PH domain undergo conformational alterations to form a disordered structure at the vesicle surface. These conformational alterations were not induced by association with inositol 1,3,4,5-tetrakisphosphate in solution or coexistence of phosphatidylcholine vesicles. Interaction with the plane of the lipid bilayer via association with the phosphoinositides is required for the unfolding of the C-terminal α-helix of the PH domain. The unwinding of the C-terminal α-helix could regulate the functions of SWAP-70 at the plasma membrane surface.