• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >A differential scanning calorimetric and P-31 NMR spectroscopic study ofthe effect of transmembrane alpha-helical peptides on thelamellar-reversed hexagonal phase transition of phosphatidylethanolaminemodel membranes
【24h】

A differential scanning calorimetric and P-31 NMR spectroscopic study ofthe effect of transmembrane alpha-helical peptides on thelamellar-reversed hexagonal phase transition of phosphatidylethanolaminemodel membranes

机译：差示扫描量热法和P-31 NMR光谱研究跨膜α-螺旋肽对磷脂酰乙醇胺模型膜的片状逆转六角相变的影响

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

We have investigated the effects of the model a-helical transmembrane peptide AC-K2L24K2-amide (L-24) on the thermotropic phase behavior of aqueous dispersions of 1,2-dielaidoylphosphatidylethanolamine (DEPE) to understand better the interactions between lipid bilayers and the membrane-spanning segments of integral membrane proteins. We studied in particular the effect of L-24 and three derivatives thereof on the liquid-crystalline lamellar (L-alpha)-reversed hexagonal (Hn) phase transition of DEPE model membranes by differential scanning calorimetry and P-31 nuclear magnetic resonance spectroscopy. We found that the incorporation of L-24 progressively decreases the temperature, enthalpy, and cooperativity of the L-alpha-H-II phase transition, as well as induces the formation of an inverted cubic phase, indicating that this transmembrane peptide promotes the formation of inverted nonlamellar phases, despite the fact that the hydrophobic length of this peptide exceeds the hydrophobic thickness of the host lipid bilayer. These characteristic effects are not altered by truncation of the side chains of the terminal lysine residues or by replacing each of the leucine residues at the end of the polyleucine core of L-24 With a tryptophan residue. Thus, the characteristic effects of these transmembrane peptides on DEPE thermotropic phase behavior are independent of their detailed chemical structure. Importantly, significantly shortening the polyleucine core of L-24 results in a smaller decrease in the L-alpha-H-II phase transition temperature of the DEPE matrix into which it is incorporated, and reducing the thickness of the host phosphatidylethanolamine bilayer results in a larger reduction in the L-alpha-H-II phase transition temperature. These results are not those predicted by hydrophobic mismatch considerations or reported in previous studies of other transmembrane ct-helical peptides containing a core of an alternating sequence of leucine and alanine residues. We thus conclude that the hydrophobicity and conformational flexibility of transmembrane peptides can affect their propensity to induce the formation of inverted nonlamellar phases by mechanisms not primarily dependent on lipid-peptide hydrophobic mismatch.
机译：我们研究了模型α-螺旋跨膜肽AC-K2L24K2-酰胺（L-24）对1,2-二乙酰基酰磷脂酰乙醇胺（DEPE）水分散体的热致相行为的影响，以更好地了解脂质双层与脂质体之间的相互作用。完整膜蛋白的跨膜段。我们特别通过差示扫描量热法和P-31核磁共振波谱研究了L-24及其三种衍生物对DEPE模型膜的液晶层状（L-α）反向六角形（Hn）相变的影响。我们发现，L-24的掺入会逐渐降低L-α-H-II相变的温度，焓和协同作用，并诱导形成倒置的立方相，这表明该跨膜肽促进了形成尽管该肽的疏水长度超过了宿主脂质双分子层的疏水厚度，但实际上却形成了反相的非薄片相。这些特征性作用不会通过末端赖氨酸残基的侧链被截短或通过用色氨酸残基代替L-24的多亮氨酸核心末端的每个亮氨酸残基而改变。因此，这些跨膜肽对DEPE热致变相行为的特征作用与其详细的化学结构无关。重要的是，显着缩短L-24的聚亮氨酸核心会导致掺入它的DEPE基质的L-α-H-II相变温度降低较小，而降低主体磷脂酰乙醇胺双层的厚度则会导致L-α-H-II相变温度的降低幅度更大。这些结果不是由疏水性错配考虑因素预测的结果，也不是先前对其他包含亮氨酸和丙氨酸残基交替序列核心的跨膜ct螺旋肽的报道。因此，我们得出结论，跨膜肽的疏水性和构象柔韧性可以通过不主要依赖脂质-肽疏水性错配的机制来影响其诱导倒置非层状相形成的倾向。

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