Membrane structure of protein kinase C and calmodulin binding domain of myristoylated alanine rich C kinase substrate determined by site-directed spin labeling.
Membrane structure of protein kinase C and calmodulin binding domain of myristoylated alanine rich C kinase substrate determined by site-directed spin labeling.
复制标题
通过定点自旋标记测定蛋白激酶 C 的膜结构和富含肉豆蔻酰化丙氨酸的 C 激酶底物的钙调蛋白结合域。
DOI：
10.1021/bi9521452
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发表时间：
1996
期刊：
影响因子：
2.9
通讯作者：
Cafiso,DS
中科院分区：
文献类型：
--
作者：
Qin,Z;Cafiso,DS
半胱氨酸取代的肽的膜，钙调蛋白，和蛋白激酶C结合结构域的肉豆蔻酰化的丙氨酸丰富的C激酶底物（MARCKS）的基础上合成和衍生化的巯基反应性乙酰基氮氧化物。这些自旋标记的肽与连续波功率饱和电子顺磁共振（EPR）光谱结合使用，以确定含有磷脂酰丝氨酸的膜上的肽的位置和结构。这些肽在膜界面结合，在中心和C-末端区域的氮氧侧链位于头基水平以下几埃。相反，肽的N-末端延伸出膜界面，使得两个N-末端残基位于头基的水侧。当与膜结合时，该肽的N-末端区段对膜表面电荷密度敏感。较高的电荷密度降低了N-末端侧链运动的幅度，并使肽的这一端更靠近膜界面。当连续的残基的位置沿着正常的双层进行比较，没有螺旋的趋势，并没有证据的聚集的肽被发现。因此，这些碱性肽在膜界面处处于延伸构型，其中疏水侧链向内朝向膜烃。
Cysteine-substituted peptides based on the membrane, calmodulin, and protein kinase C binding domain of the myristoylated alanine rich C kinase substrate (MARCKS) were synthesized and derivatized with a sulfhydryl reactive proxyl nitroxide. These spin-labeled peptides were used in combination with continuous wave power saturation electron paramagnetic resonance (EPR) spectroscopy to determine the position and structure of the peptide on membranes containing phosphatidylserine. These peptides bind at the membrane interface, with nitroxide side chains in the central and C-terminal regions lying several angstroms below the level of the head group. In contrast, the N-terminus of the peptide is extended out of the membrane interface so that the two N-terminal residues are positioned on the aqueous side of the head group. When bound to the membrane, the N-terminal segment of this peptide is sensitive to the membrane surface charge density. Higher charge densities decrease the amplitude of side chain motions at the N-terminus and bring this end of the peptide closer to the membrane interface. When the location of successive residues along the bilayer normal is compared, no helical trend is seen, and no evidence for aggregation of the peptide is found. The EPR spectra of double spin-labeled peptides also show no evidence for a helical structure. Thus, these basic peptides are in an extended configuration at the membrane interface with hydrophobic side chains oriented inward toward the membrane hydrocarbon.