SYNTHESES OF LABELED HEMES FOR PROTEIN NMR STUDIES

血红素在预定位置用氘进行区域选择性标记， 碳13和氟将用作核磁共振探针来了解 超精细位移与结构/功能之间的关系 生物学上重要的血红素蛋白（如肌红蛋白）的相关性， 血红蛋白、细胞色素和过氧化物酶；拟议的工作将有助于 了解血红素蛋白功能以及结构和电子 导致贫血等多种衰弱性疾病的因素。 的 合成标记材料也将用于制作最终的条带 共振拉曼光谱以及电子研究中的作业 顺磁特性。 经过化学或生物合成后 重组为适当的脱辅基蛋白，合成的化合物将 用于通过差异分配血红素相关共振 质子光谱，以及直接在氘、碳 13 和 氟光谱。 综合时将遵循两种基本方法 标记的血红素；碳13和一些氘标记的衍生物 由无环全合成得到原卟啉-IX 使用我们最近开发的三吡二烯方法的前体，以及 铜催化 a,c-联二烯的环化（其机制将 也有待研究）。 单内消旋氘化和碳 13 标记的衍生物 原卟啉-IX 也将被合成以测试血红素的 NMR 模型 分解代谢为胆红素（与肝脏问题有关，例如 黄疸和高胆红素血症），在这方面，核磁共振谱 氧代绿蛋白/蛋白质聚集体也将被研究。 第二条路线 标记的血红素将利用原卟啉-IX 上的氘交换， 直接给出所需的标记血红素，并将尝试 在电子结构的基础上使交换过程合理化 卟啉核内。 氟和一些碳 13 标记的血红素 将通过原卟啉-IX衍生物的修饰来制备。 某些 新颖的、未标记的卟啉也将被合成，或者通过总 合成或通过修改现有的市售样品； 它们将用于核磁共振研究，以及拟议的共振拉曼， X 射线和电子顺磁共振研究。

Hemes regioselectively labeled in predetermined positions with deuterium, carbon-13, and fluorine will be used as NMR probes to gain an understanding of the relationship between hyperfine shifts and structure/function correlations in biologically important heme proteins such as myoglobins, hemoglobins, cytochromes,and peroxidases; the proposed work will facilitate understanding of heme protein function, and of structural and electronic factors with cause several debilitating diseases such as anemias. The synthelic labeled materials will also be used for making definitive band assignments in resonance Raman spectra, and also in studies of electron paramagnetic characteristics. After either chemical or biosynthetic reconstitution into appropriate apoproteins, the synthetic compounds will be used to enable assignment of heme associated resonances by difference spectroscopy for protons, and directly in the deuterium, carbon-13, and fluorine spectra. Two fundamental approaches will be followed in synthesis of the labeled hemes; carbon-13 and some deuterium labeled derivatives of protoporphyrin-IX will be obtained through total synthesis from acyclic precursors using our recently developed tripyrrene approaches, and cupric-catalyzed cyclization of a,c-biiadienes (the mechanism of which will also be studied). A mono-meso-deuterated, and carbon-13 labeled derivative of protoporphyrin-IX will also be synthesized to test an NMR model for heme catabolism to bilirubin (which is associated with hepatic problems such as jaundice and hyperbilirubinemia), and in this connection, NMR spectra of oxophlorin/protein aggregates will also be investigated. The second route to labeled hemes will utilize deuterium exchange on protoporphyrin-IX, to give directly the required labeled hemes and an attempt will be made to rationalize the exchange processes on the basis of electronic structure within the porphyrin nucleus. Fluorine and some carbon-13 labeled hemes will be prepared by modification of protoporphyrin-IX derivatives. Certain novel, unlabeled porphyrins will also be synthesized, either by total synthesis or by modification of existing commercially available samples; they will be used in NMR studies, and also in proposed resonance Raman, X-ray and electron paramagnetic resonance investigations.