SYNTHESES OF LABELED HEMES FOR PROTEIN NMR STUDIES

在预定位置用氘区域选择性标记的血红素， 碳-13和氟将被用作核磁共振探针， 超精细位移和结构/功能之间的关系 生物学上重要的血红素蛋白如肌红蛋白， 血红蛋白，细胞色素和过氧化物酶;拟议的工作将促进 了解血红素蛋白的功能，结构和电子 导致贫血等多种衰弱性疾病的因素。 的 酶标材料也将用于制备确定性条带 在共振拉曼光谱的分配，也在电子的研究 顺磁特性 经过化学或生物合成 重组成适当的脱辅基蛋白，合成的化合物将 用于能够通过差异来分配血红素相关共振 光谱的质子，并直接在氘，碳-13， 氟光谱 在综合中将遵循两种基本方法 的标记血红素;碳-13和一些氘标记的衍生物 原卟啉-IX将通过全合成从无环 前体使用我们最近开发的三吡咯方法，和 铜催化的α，β-联二烯的环化（其机理将 也要研究）。 一种单中位氘代和碳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 胆红素（与肝脏问题有关， 黄疸和高胆红素血症），并在这方面，NMR谱 还将研究oxophlorin/蛋白质聚集体。 第二路由 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标记的血红素 将通过修饰原卟啉-IX衍生物来制备。 某些 新的，未标记的卟啉也将被合成，无论是通过总 合成或通过对现有市售样品进行改性; 它们将用于NMR研究，也用于提出的共振拉曼， 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.