Correlation of Vesicle Binding and Phospholipid Dynamics with Phospholipase C Activity
Correlation of Vesicle Binding and Phospholipid Dynamics with Phospholipase C Activity
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囊泡结合和磷脂动力学与磷脂酶 C 活性的相关性
DOI：
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发表时间：
2009
影响因子：
4.8
通讯作者：
M. Roberts
中科院分区：
文献类型：
--
作者：
Mingming Pu;X.;A. Redfield;A. Gershenson;M. Roberts
的外周膜蛋白，磷脂酰肌醇特异性磷脂酶C（PI-PLC）的酶活性，增加了非底物磷脂与增强调谐的膜脂质组合物的程度。对于苏云金芽孢杆菌PI-PLC，少量的磷脂酰胆碱（PC）激活酶向其底物PI;高于0.5摩尔分数PC（XPC），酶活性大幅下降。为了提供这种PC依赖性行为的分子基础，我们使用荧光相关光谱来探索酶与由PC和阴离子磷脂组成的多组分脂质囊泡的结合（其结合到活性位点作为底物类似物），并使用高分辨率场循环31 P NMR方法来估计磷脂头基运动的内部相关时间（τc）。PI-PLC与纯阴离子磷脂囊泡的结合较差，但0.1 XPC显著增强结合，增加PI-PLC活性，并减慢两种磷脂头基的纳秒旋转/摆动运动，如τc增加所示。PI-PLC活性和磷脂τc在0.1和0.5 XPC之间恒定。在此PC含量以上，PI-PLC对底物类似物几乎没有额外的影响，但进一步减缓了PC τc，这是一种与酶活性降低相关的运动变化。对于PC丰富的双层，这些变化，连同降低的顺序参数和增强的侧向扩散的底物类似物在PI-PLC的存在下，意味着在高XPC，动力学抑制PI-PLC的结果从囊内螯合的酶从大部分的基板。这两种方法提供了一个详细的蛋白质-脂质相互作用的视图，可以很容易地适应其他外周膜蛋白。
The enzymatic activity of the peripheral membrane protein, phosphatidylinositol-specific phospholipase C (PI-PLC), is increased by nonsubstrate phospholipids with the extent of enhancement tuned by the membrane lipid composition. For Bacillus thuringiensis PI-PLC, a small amount of phosphatidylcholine (PC) activates the enzyme toward its substrate PI; above 0.5 mol fraction PC (XPC), enzyme activity decreases substantially. To provide a molecular basis for this PC-dependent behavior, we used fluorescence correlation spectroscopy to explore enzyme binding to multicomponent lipid vesicles composed of PC and anionic phospholipids (that bind to the active site as substrate analogues) and high resolution field cycling 31P NMR methods to estimate internal correlation times (τc) of phospholipid headgroup motions. PI-PLC binds poorly to pure anionic phospholipid vesicles, but 0.1 XPC significantly enhances binding, increases PI-PLC activity, and slows nanosecond rotational/wobbling motions of both phospholipid headgroups, as indicated by increased τc. PI-PLC activity and phospholipid τc are constant between 0.1 and 0.5 XPC. Above this PC content, PI-PLC has little additional effect on the substrate analogue but further slows the PC τc, a motional change that correlates with the onset of reduced enzyme activity. For PC-rich bilayers, these changes, together with the reduced order parameter and enhanced lateral diffusion of the substrate analogue in the presence of PI-PLC, imply that at high XPC, kinetic inhibition of PI-PLC results from intravesicle sequestration of the enzyme from the bulk of the substrate. Both methodologies provide a detailed view of protein-lipid interactions and can be readily adapted for other peripheral membrane proteins.
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磷脂酰肌醇特异性磷脂酶 C 向肌醇 1,2-（环）-磷酸的激活。
DOI：
10.1021/bi960601w
发表时间：
1997
期刊：
Biochemistry.
影响因子：
--
作者：
Zhou,C;Wu,Y;Roberts,MF
通讯作者：
Roberts,MF
影响因子：
2.9
作者：
Guo, Su;Zhang, Xin;Roberts, Mary F.
通讯作者：
Roberts, Mary F.
影响因子：
3.4
作者：
Rusu, L;Gambhir, A;Rädler, J
通讯作者：
Rädler, J
研究细菌磷脂酰肌醇特异性磷脂酶 C 的界面结合。
DOI：
10.1021/bi034195
发表时间：
2003
期刊：
Biochemistry.
影响因子：
--
作者：
Wehbi,Hania;Feng,Jianwen;Kolbeck,James;Ananthanarayanan,Bharath;Cho,Wonhwa;Roberts,MaryF
通讯作者：
Roberts,MaryF
影响因子：
3.4
作者：
Hess, ST;Webb, WW
通讯作者：
Webb, WW