Toxic Metal Complexation by de Novo Designed Peptides

描述(申请人提供)：由汞、铅、镉和砷等元素引起的重金属中毒是一个严重的人类健康问题。了解重金属与蛋白质的相互作用对于确定毒性机制、开发将人体暴露降至最低的方法以及提供去除有毒离子的治疗方案至关重要。 我们的目标是(1)开发为理解金属调节蛋白和金属配位伴侣提供基础的多肽系统，(2)开发能够有效和选择性地从水溶液中隔离重金属离子的多肽系统，以及(3)了解金属与这些设计的多肽结合的热力学和动力学。 为了实现这些目标，我们将使用一个基于三链卷曲多肽聚集基序的从头肽系统，该基序包裹着高亲和力的单一重金属离子，并提供生物系统中汞、镉和砷结合位置的光谱模型。我们将在存在和不存在这些重金属的情况下生成该多肽体系的高分辨结构，阐明重金属包裹的动力学和热力学机制，并将表征体系的阵列扩展到过渡金属离子Fe(II)、Cu(I)、Ni(II)、Co(II)和Zn(II)。我们还将扩展原始设计，以包括包裹重金属的单链多肽和提供与原始设计不同的配位环境的卷曲，以及那些封装多个重金属离子的单链多肽。 这些研究将扩大科学界研究金属肽设计、金属调节蛋白和重金属解毒所奠定的知识基础。这些目标将有助于深入了解金属配位和肽链结构之间的相互作用，从而确定整个金属肽折叠，这是金属肽设计的一个重要方面。此外，开发高效和特定的重金属截留肽最终可以提供一种可行的、可生物降解的方法来去除受污染的水中的重金属。

DESCRIPTION (provided by applicant): Heavy metal poisoning by elements such as mercury, lead, cadmium, and arsenic is a significant human health problem. Understanding the interaction of heavy metals with proteins is essential for defining the mechanism of toxicity, developing ways to minimize human exposure and to provide therapeutic regimens for removal of toxic ions. Our goals are (1) to develop peptide systems that provide a groundwork for the understanding of metalloregulatory proteins and metallochaperones, (2) to develop peptidic systems that can efficiently and selectively sequester heavy metal ions from aqueous solutions, and (3) to understand the thermodynamics and kinetics of metal binding to these designed peptides. To achieve these goals we will use a de novo peptide system based on the three-stranded coiled coil peptide aggregate motif that encapsulates with high affinity single heavy metal ions and provides spectroscopic models of mercury, cadmium and arsenic binding sites in biological systems. We will generate high resolution structures of this peptide system in the presence and absence of these heavy metals, elucidate the kinetic and thermodynamic mechanisms of heavy metal encapsulation, and expand the array of characterized systems to transition metal ions Fe(II), Cu(I), Ni(II), Co(II) and Zn(II). We will also extend the original design to include single chain peptides that encapsulate heavy metals and coiled coils that provide different coordination environments than the original design and those that encapsulate more than one heavy metal ion. These studies will expand the foundation of knowledge that has been laid by the scientific community investigating metallopeptide design, metalloregulatory proteins and heavy metal detoxification. These objectives will develop insight into the interplay between metal coordination and apopeptide structure in defining the overall metallopeptide fold, an important aspect of metallopeptide design. Also, development of highly efficient and specific heavy metal sequestering peptides could, ultimately, provide a viable and biodegradable means of removing heavy metals from contaminated water.