SYNTHESES OF LABELED HEMES FOR PROTEIN NMR STUDIES

亚铁血红素区域选择性地标记在预定的位置上， 碳-13和氟将被用作核磁共振探针，以了解 超精细位移与结构/功能的关系 肌红蛋白等生物上重要的血红素蛋白之间的相关性， 血红蛋白、细胞色素和过氧化物酶；拟议的工作将促进 对血红素蛋白功能、结构和电子的理解 一些因素会导致几种衰弱的疾病，如贫血。这个 合成的标记材料也将被用于制作最终的条带 共振拉曼光谱的指认以及电子的研究 顺磁特性。在化学或生物合成之后 重组成适当的脱辅基蛋白，合成的化合物将 用于实现通过差异来分配与血红素相关的共振 质子的光谱，以及直接在氢、碳-13和 氟光谱。在综合中将遵循两种基本方法 标记的血红素；碳-13和一些氢标记的衍生物 原卟啉-IX将由无环化合物通过全合成得到 使用我们最近开发的三苯并四茂铁方法的前体，以及 铜催化的a，c-联二烯的环化反应(其机理将 也有待研究)。一种单中氢碳13标记的衍生物 还将合成原卟啉-IX，以测试血红素的核磁共振模型 分解代谢为胆红素(这与肝脏问题有关，如 黄疸和高胆红素血症)，并在这方面，核磁共振谱 此外，还将对氧磷酸盐/蛋白质聚集体进行研究。第二条路线 TO标记的氯化血红素将利用原卟啉-IX上的氢交换，TO 直接给出所需的标记血红素，将尝试 在电子结构的基础上使交换过程合理化 在卟啉核内。氟和一些碳-13标记的氯化血红素 将通过对原卟啉-IX衍生物进行修饰来制备。一定的 新的，未标记的卟啉也将被合成，无论是由全 合成或通过对现有的商业样品进行修改； 它们将用于核磁共振研究，也将用于拟议的共振拉曼， 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.