The structural characterization of de novo designed metalloproteins together with determination of chemical reactivity can provide a detailed understanding of the relationship between protein structure and functional properties. Toward this goal, we have prepared a series of cyclic peptides that bind to water-soluble metalloporphyrins (FeIII and CoIII). Neutral and positively charged histidine-containing peptides bind with a high affinity, whereas anionic peptides bind only weakly to the negatively charged metalloporphyrin. Additionally, it was found that the peptide becomes helical only in the presence of the metalloporphyrin. CD experiments confirm that the metalloporphyrin binds specific cyclic peptides with high affinity and with isodichroic behavior. Thermal unfolding experiments show that the complex has ”native-like” properties. Finally, NMR spectroscopy produced well dispersed spectra and experimental restraints that provide a high-resolution solution structure of the complexed peptide.
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机译:从头设计的金属蛋白的结构特征以及化学反应性的确定可以提供对蛋白质结构与功能特性之间关系的详细了解。为了实现这一目标,我们制备了一系列与水溶性金属卟啉(Fe III sup>和Co III sup>)结合的环肽。中性和带正电的含组氨酸的肽以高亲和力结合,而阴离子肽仅与带负电的金属卟啉弱结合。另外,发现该肽仅在金属卟啉存在下才变成螺旋形。 CD实验证实,金属卟啉以高亲和力和等色行为结合特定的环肽。热展开实验表明该配合物具有“天然”性质。最终,NMR光谱产生了分散良好的光谱和实验约束条件,为复合肽提供了高分辨率的溶液结构。
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