Probing the helical tilt and dynamic properties of membrane-bound phospholamban in magnetically aligned bicelles using electron paramagnetic resonance spectroscopy
Probing the helical tilt and dynamic properties of membrane-bound phospholamban in magnetically aligned bicelles using electron paramagnetic resonance spectroscopy
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DOI：
10.1016/j.bbamem.2011.11.030
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发表时间：
2012-03-01
影响因子：
3.4
通讯作者：
Lorigan, Gary A.
中科院分区：
文献类型：
--
作者：
Ghimire, Harishchandra;Abu-Baker, Shadi;Lorigan, Gary A.
野生型受磷蛋白 (WT-PLB) 是肌浆网膜中的一种 Ca2+-ATP 酶 (SERCA) 调节剂，使用 TOAC 硝基氧自旋标记、磁对准 bicelles 和电子顺磁共振 (EPR) 光谱来研究以确定结构和动态信息。使用刚性 TOAC 自旋标记探测 PLB 的不同结构域（跨膜片段：位置 42 和 45、环区域：位置 20 和细胞质结构域：位置 10），以提取跨膜螺旋倾斜和结构动态信息，这对于理解 PLB 在调节 Ca2+-ATPase 活性中的调节功能至关重要。比对实验表明，野生型 PLB 的跨膜结构域在 DMPC/DHPC bicelles 中具有 13 度+/- 4 度的螺旋倾斜。放置在 WT-PLB 跨膜域上的 TOAC 自旋标签显示出高度受限的运动，旋转相关时间超过 100 ns (tau(c))；而环和细胞质区域各自由两种不同的运动动力学组成：一个是亚纳秒尺度的快速分量，另一个分量是纳秒范围内的较慢动力学。 (C) 2011 Elsevier B.V. 保留所有权利。
Wild-type phospholamban (WT-PLB), a Ca2+-ATPase (SERCA) regulator in the sarcoplasmic reticulum membrane, was studied using TOAC nitroxide spin labeling, magnetically aligned bicelles, and electron paramagnetic resonance (EPR) spectroscopy to ascertain structural and dynamic information. Different structural domains of PLB (transmembrane segment: positions 42 and 45, loop region: position 20, and cytoplasmic domain: position 10) were probed with rigid TOAC spin labels to extract the transmembrane helical tilt and structural dynamic information, which is crucial for understanding the regulatory function of PLB in modulating Ca2+-ATPase activity. Aligned experiments indicate that the transmembrane domain of wild-type PLB has a helical tilt of 13 degrees +/- 4 degrees in DMPC/DHPC bicelles. TOAC spin labels placed on the WT-PLB transmembrane domain showed highly restricted motion with more than 100 ns rotational correlation time (tau(c)); whereas the loop, and the cytoplasmic regions each consists of two distinct motional dynamics: one fast component in the sub-nanosecond scale and the other component is slower dynamics in the nanosecond range. (C) 2011 Elsevier B.V. All rights reserved.