...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Conformational Changes of an Exchangeable Apolipoprotein, Apolipophorin III from Locusta migratoria, at Low pH: Correlation with Lipid Binding
【24h】

Conformational Changes of an Exchangeable Apolipoprotein, Apolipophorin III from Locusta migratoria, at Low pH: Correlation with Lipid Binding

机译：在低pH下可交换的载脂蛋白，来自东方蝗的载脂蛋白III的构象变化：与脂质结合的相关性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Locusta migratoria apolipophorin ill (apoLp-m) is a helix bundle exchangeable apolipoprotein that reversibly binds to lipoprotein surfaces. Structural reorganization of its five amphipathic a-helices enables the transition from the lipid-free to lipid-bound state. ApoLp-m-induced transformation of dimyristoylphosphatidylcholine (DMPC) bilayer vesicles into smaller discoidal complexes is enhanced as a function of decreasing pH, with maximal transformation occurring at pH 3.5. Over the entire pH range studied, apoLp-m retains nearly all of its secondary structure content. Whereas no changes in fluorescence emission maximum of the two Trp residues in apoLp-m were observed in the pH range from 7.0 to 4.0, a further decrease in pH resulted in a strong red shift. Near-UV circular dichroism spectra of apoLp-m showed well-defined extrema (at 286 and 292 nm) between pH 7.0 and pH 4.0, which were attributed to Trpl15. Below pH 4.0, these extrema collapsed, indicating a less rigid environment for Trpl15. Similarly, the fluorescence intensity of 8-anilinonaphthalene-l-sulfonate in the presence of apoLp- ill increased 4-fold below pH 4.0, indicating exposure of hydrophobic sites in the protein in this pH range. Taken together, the data suggest two conformational states of the protein. In the flfSt state between pH 7.0 and pH 4.0, apoLp-m retains a nativelike helix bundle structure. The second state, found between pH 3.0 and pH 4.0, is reminiscent of a molten globule, wherein tertiary structure contacts are disrupted without a significant loss of secondary structure content. In both states DMPC vesicle transformation is enhanced by lowering the solution pH, reaching an optimum in the second state. The correlation between tertiary structure and lipid binding activity suggests that helix bundle organization is a determinant of apoLp-m lipid binding activity.
机译：南方蝗菌载脂蛋白（ApoLp-m）是一种螺旋束可交换载脂蛋白，可逆地结合到脂蛋白表面。它的五个两亲性a螺旋的结构重组使从无脂质状态转变为脂质结合状态。 ApoLp-m诱导的二肉豆蔻酰基磷脂酰胆碱（DMPC）双层囊泡向较小盘状复合物的转化随pH降低而增强，在pH 3.5时发生最大转化。在研究的整个pH范围内，apoLp-m几乎保留了其所有二级结构成分。尽管在7.0至4.0的pH范围内，在apoLp-m中没有观察到两个Trp残基的最大荧光发射变化，但pH的进一步降低导致强烈的红移。 apoLp-m的近紫外圆二色性光谱显示在7.0和4.0之间的明确的极值（在286和292 nm处），这归因于Trpl15。在pH 4.0以下，这些极值塌陷，表明Trpl15的刚性环境较差。类似地，在apoLill存在下，8-苯胺基萘-1-磺酸盐的荧光强度在pH 4.0以下增加了4倍，表明在此pH范围内蛋白质中的疏水位点暴露。两者合计，数据表明蛋白质的两个构象状态。在pH 7.0和pH 4.0之间的flfSt状态下，apoLp-m保留了天然的螺旋束结构。在pH 3.0和pH 4.0之间发现的第二种状态让人联想到熔融小球，其中三级结构接触被破坏，而二级结构含量没有明显损失。在两种状态下，通过降低溶液的pH值均可增强DMPC囊泡转化，在第二种状态下达到最佳状态。三级结构与脂质结合活性之间的相关性表明螺旋束组织是apoLp-m脂质结合活性的决定因素。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号