Uncoupling hydrophobicity and helicity in transmembrane segments -: α-helical propensities of the amino acids in non-polar environments
Uncoupling hydrophobicity and helicity in transmembrane segments -: α-helical propensities of the amino acids in non-polar environments
复制标题
DOI：
10.1074/jbc.273.37.23645
复制
发表时间：
1998-09-11
影响因子：
4.8
通讯作者：
Deber, CM
中科院分区：
文献类型：
--
作者：
Liu, LP;Deber, CM
尽管跨膜蛋白质中的氨基酸链呈螺旋状且具有疏水性，但对于膜的非极性环境中单个氨基酸的螺旋倾向范围却关注甚少。由于将基于可溶性蛋白质的结构预测算法应用于膜蛋白是不合适的，我们使用了从头设计的肽（KKAAAXAAAAAXAAWAAXAAAKKKK - 酰胺，其中X代表20种常见氨基酸中的一种），它模拟蛋白质跨膜结构域，以确定在正丁醇的各向同性非极性环境中每个残基的α - 螺旋倾向。通过圆二色光谱法测量的肽的螺旋度在正丁醇中从θ(222)= -17,000度（脯氨酸）到 -38,800度（色氨酸）不等。结果表明，每种氨基酸的相对螺旋度与其在天然跨膜片段中的出现频率密切相关，这意味着单个残基的螺旋倾向与其疏水性共同作用可能是膜中蛋白质片段构象的关键决定因素。
Although the chains of amino acids in proteins that span the membrane are demonstrably helical and hydrophobic, little attention has been paid toward addressing the range of helical propensities of individual amino acids in the non-polar environment of membranes. Because it is inappropriate to apply soluble protein-based structure prediction algorithms to membrane proteins, we have used de novo designed peptides (KKAAAXAAAAAXAAWAAXAAAKKKK-amide, where X indicates one of the 20 commonly occurring amino acids) that mimic a protein membrane-spanning domain to determine the cu-helical proclivity of each residue in the isotropic non-polar environment of n-butanol, Peptide helicities measured by circular dichroism spectroscopy were found to range from theta(222) = -17,000 degrees (Pro) to -38,800 degrees (ne) in n-butanol, The relative helicity of each amino acid is shown to be well correlated with its occurrence frequency in natural transmembrane segments, indicating that the helical propensity of individual residues in concert with their hydrophobicity may be a key determinant of the conformations of protein segments in membranes.