FTIR spectroscopic studies of the conformation and amide hydrogen exchange of a peptide model of the hydrophobic transmembrane alpha-helices of membrane proteins.
FTIR spectroscopic studies of the conformation and amide hydrogen exchange of a peptide model of the hydrophobic transmembrane alpha-helices of membrane proteins.
复制标题
膜蛋白疏水跨膜 α 螺旋肽模型的构象和酰胺氢交换的 FTIR 光谱研究。
DOI：
10.1021/bi00161a041
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发表时间：
1992
期刊：
影响因子：
2.9
通讯作者：
R. McElhaney
中科院分区：
文献类型：
--
作者：
Y. Zhang;R. Lewis;R. Hodges;R. McElhaney
用傅里叶变换红外光谱研究了疏水肽Lys 2-Gly-Leu 24-Lys 2-Ala-amide的构象和酰胺氢交换。在这些研究中，通过检查酰胺I和酰胺II吸收带的轮廓，获得了有关肽二级结构的信息。构象敏感的酰胺I和酰胺II区域的红外光谱表明，肽主要是α-螺旋，它包含一些非α-螺旋结构，这可能是在一个扩展的构象。的肽的酰胺质子的交换率的研究表明，有两个群体的酰胺质子显着不同的相对于它们的交换率与散装溶剂相，无论是肽溶解在甲醇中或分散在水合脂质双层。一个群体的酰胺质子是非常容易交换的，我们的数据表明，它主要是由肽的扩展区域，但不完全是。另一个群体与本体溶剂交换非常缓慢，似乎完全源自肽的α-螺旋结构域。当肽分散在水合磷脂酰胆碱双层中时，后一种群体实际上是不可交换的，但当肽用甲醇溶解时，可以在很大程度上交换。我们认为，这种缓慢交换的酰胺质子的人口产生的疏水聚亮氨酸核心的中心部分，形成一个非常稳定的α-螺旋，将深深地埋在水化脂质双层的疏水结构域。（250字处删节）
The conformation and amide hydrogen exchangeability of the hydrophobic peptide Lys2-Gly-Leu24-Lys2-Ala-amide were studied by Fourier transform infrared spectroscopy. In these studies information on the secondary structure of the peptide was obtained from an examination of the contours of both the amide I and amide II absorption bands. The conformationally sensitive amide I and amide II regions of the infrared spectra suggest that the peptide is predominantly alpha-helical and that it contains some non-alpha-helical structures which are probably in an extended conformation. Studies of the exchangeability of the amide protons of the peptide indicate that there are two populations of amide protons which differ markedly with respect to their exchangeability with the bulk solvent phase, whether the peptide is dissolved in methanol or dispersed in hydrated lipid bilayers. One population of amide protons is very readily exchangeable, and our data suggest that it arises primarily but not exclusively from the extended regions of the peptide. The other population exchanges very slowly with the bulk solvent and appears to originate entirely from the alpha-helical domain of the peptide. This latter population is virtually unexchangeable when the peptide is dispersed in hydrated phosphatidylcholine bilayers but can be largely exchanged when the peptide is solubilized with methanol. We suggest that this slowly exchanging population of amide protons arises from the central part of the hydrophobic polyleucine core which forms a very stable alpha-helix that would be deeply buried in the hydrophobic domain of hydrated lipid bilayers.(ABSTRACT TRUNCATED AT 250 WORDS)