MagicWand:: A single, designed peptide that assembles to stable, ordered α-helical fibers
MagicWand:: A single, designed peptide that assembles to stable, ordered α-helical fibers
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DOI：
10.1021/bi801072s
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发表时间：
2008-09-30
期刊：
影响因子：
2.9
通讯作者：
Woolfson, Derek N.
中科院分区：
文献类型：
--
作者：
Gribbon, Christopher;Channon, Kevin J.;Woolfson, Derek N.
我们描述了一种简单的单肽设计，它可以自组装成具有显著稳定性和秩序的延伸和加厚的纳米到中尺度纤维。设计的基本底盘是众所周知的二聚体-螺旋线圈图案。因此，该肽具有七肽序列重复abcdefg，在a和d位点有异亮氨酸和亮氨酸残基，以确保二聚化。此外，为了指导多肽的交错组装和促进纤维形成，即与钝端离散物种相反，多肽的末端是阳离子的，中间半部分是阴离子的，赖氨酸和谷氨酸分别位于核心侧翼的e和g位置。这种+、-、-、+的排列方式使这种肽得名“魔棒”（MW）。根据圆二色性（CD）光谱判断，MW在亚微摩尔及以上的范围内组装成α螺旋结构。在100 μ M多肽浓度下，MW的热展开是可逆的，熔化温度为70℃。负染色透射电子显微镜（TEM）的MW组件显示硬，直，纤维棒延伸数十微米。此外，不同的污渍在垂直和平行于纤维长轴上都突出了相当大的顺序。这些特征的尺寸与长而直的螺旋螺旋线圈束相一致，其轴线平行于纤维的长轴。纤维增厚表明盘绕线圈相互作用。肽外表面的诱变-即。结合稳定性和显微镜测量，强调了静电和阳离子- π相互作用在驱动纤维形成、稳定性和增厚中的作用。这些发现是在越来越多的自组装肽基纤维系统的背景下讨论的。
We describe a straightforward single-peptide design that self-assembles into extended and thickened nano-to-mesoscale fibers of remarkable stability and order. The basic chassis of the design is the well-understood dimeric a-helical coiled-coil motif. As such, the peptide has a heptad sequence repeat, abcdefg, with isoleucine and leucine residues at the a and d sites to ensure dimerization. In addition, to direct staggered assembly of peptides and to foster fibrillogenesis-that is, as opposed to blunt-ended discrete species-the terminal quarters of the peptide are cationic and the central half anionic with lysine and glutamate, respectively, at core-flanking e and g positions. This +,-,-,+ arrangement gives the peptide its name, MagicWand (MW). As judged by circular dichroism (CD) spectra, MW assembles to alpha-helical structures in the sub-micromolar range and above. The thermal unfolding of MW is reversible with a melting temperature > 70 degrees C at 100 mu M peptide concentration. Negative-stain transmission electron microscopy (TEM) of MW assemblies reveals stiff, straight, fibrous rods that extended for tens of microns. Moreover, different stains highlight considerable order both perpendicular and parallel to the fiber long axis. The dimensions of these features are consistent with bundles of long, straight coiled alpha-helical coiled coils with their axes aligned parallel to the long axis of the fibers. The fiber thickening indicates intercoiled-coil interactions. Mutagenesis of the outer surface of the peptide-i.e., at the b and f positions-combined with stability and microscopy measurements, highlights the role of electrostatic and cation-pi interactions in driving fiber formation, stability and thickening. These findings are discussed in the context of the growing number of self-assembling peptide-based fibrous systems.