TOTAL CHEMICAL SYNTHESIS OF CADPR AND CADPR ANALOGS

环腺苷二磷酸核糖（cADPR）似乎是一种新的， 重要的第二信使，介导Ca 2+释放。 绝大多数 文献中cADPR制备的主要方法是酶法合成。 体内 在体外，ADP-核糖基环化酶催化nAD+转化为 cADPR。 最近，从NAD+仿生化学合成cADPR， 被举报。 本文首次非酶促全化学合成 cADPR被提出。 这样的综合是最终 cADPR光亲和标记物（帕尔斯）的全化学合成，因为它是 合成cADPR的现有方法不太可能 充分修改。 cADPR无环前体将由以下物质制备： 核苷酸和糖苷结构单元。 这些无环前体可以是 “武装”并被激活以形成氧碳正离子和闭环 使用弗雷泽-里德的方法。 这种分析是基于共同的 在仿生学和生物化学中氧碳正离子中间体的中间性 NAD+的酶促环化和Fraser-Reid的工作。 拟议 合成的优点是它易于用于构建cADPR 类似物，包括cADPR帕尔斯和cADPR亲和层析（AC） 配体。 随着cADPR及其类似物的化学合成方法的掌握， 将把我们的注意力转向cADPR的生化评价 类似物 预期特异性构建的cADPR帕尔斯和AC配体 是鉴定、纯化和分离cADPR的宝贵工具 受体、效应子和结合蛋白。 生物活性测定 光亲和标记实验将使用原始的海胆卵 系统，长期目标是开发一套通用的 研究这种新的Ca 2+介导的第二信使系统的工具。 的 在这项工作中获得的知识和方法预计将 为我们理解这一点做出了重要贡献， 其他第二信使途径。 如果实验证明 成功的话，我们将有能力大大扩大 该项目包括比海胆更复杂的系统。

Cyclic adenosine diphosphate ribose (cADPR) appears to be a new and important second messenger that mediates Ca2+ release. The large majority of cADPR preparations in the literature are enzymatic syntheses. in vivo and in vitro, ADP-ribosyl cyclase catalyzes the conversion of nAD+ to cADPR. A biomimetic chemical synthesis of cADPR from NAD+ has recently been reported. Herein the first non-enzymatic total chemical synthesis of cADPR is proposed. Such a synthesis is a prerequisite to the eventual total chemical synthesis of cADPR photoaffinity labels (PALs) because it is unlikely that the available methods for the synthesis of cADPR can be sufficiently modified. cADPR acyclic precursors will be prepared from nucleotide and glycoside building blocks. These acyclic precursors can be "armed" and activated towards oxocarbenium ion formation and ring closure using the methodology of Fraser-Reid. This analysis is based on the common intermediacy of oxocarbenium ions intermediates in the biomimetic and enzymatic cyclizations of NAD+ and in Fraser-Reid's work. The proposed synthesis has the advantage that it is easily adapted to construct cADPR analogues, including cADPR PALs and cADPR affinity chromatography (AC) ligands. With a method for the chemical synthesis of cADPR and analogues in hand we will turn our attention to the biochemical evaluation of the cADPR analogues. Specifically constructed cADPR PALs and AC ligands are expected to be invaluable tools for identifying, purifying, and isolating cADPR receptor, effector, and binding proteins. Assays for biological activity and photoaffinity labeling experiments will use the original sea urchin egg systems, with the long term goal being the development of a set of general tools to study this new Ca2+-mediated second messenger system. The knowledge and methodology gained in the course of this work are expected to make important contributions to our understanding of this and potentially other second messenger pathways. Should the proposed experiments prove successful we would then be equipped to significantly expand the scope of the project to include systems more complex than the sea urchin.