BIOLOGICALLY-IMPORTANT FURANOSYL RINGS

生物学上重要的呋喃糖的几种性质（即，溶液 组成和构象以及开环和闭环动力学 将研究反应（互变异构化）。 实验方法 涉及：A.呋喃糖和呋喃糖结构变体的合成 所有环构型的磷酸盐，以允许结构-功能 比较。 化合物将用稳定同位素（13 C，2 H）标记， 便于通过高场NMR光谱进行检查。 B。中存在的互变异构形式的鉴定和定量 通过NMR测定呋喃糖的水溶液，特别注意 羰基和水合物形式。 C.三键1H-1H的测量和构象解释， ~（13）C-~（13）H和~（13）C-~（13）C耦合常数与自旋-晶格（T1）弛豫 倍（13 C，1H）的呋喃糖基环。 放松研究将涉及 使用DESERT和动态NOE NMR方法获得绝对1H-1H 核间距离，从中将评估构象。 通过NMR推导出的优选环构象将与那些 通过MO计算预测。 D.单向速率常数的测量和解释 通过NMR进行呋喃糖互变异构化。 将测量激活参数 对于每个组分反应。 简单呋喃糖的溶液研究将扩展到 核糖核苷和寡核糖核苷酸。 几个GC丰富 寡核糖核苷酸，其碱基序列与 E.大肠杆菌tRNAglu，将制备含有 全氘代呋喃核糖基残基，以促进其NMR研究 解决方案结构。 拟议的研究是追求长期目标的先决条件。 确定结合特异性的分子基础的目的 核酸和蛋白质之间的关系，以及阐明糖的作用 互变异构对代谢调节的影响。

Several properties of biologically-important furanoses (i.e., solution composition and conformation, and kinetics of ring-opening and ring-closing reactions (tautomerization) will be studied. The experimental approach involves: A. Synthesis of structural variants of furanoses and furanose phosphates in all ring configurations to permit structure-function comparisons. Compounds will be labeled with stable isotopes (13C, 2H) to facilitate examination by high-field NMR spectroscopy. B. Identification and quantitation of the tautomeric forms present in aqueous solutions of furanoses by NMR, with particular attention given to carbonyl and hydrate forms. C. Measurement and conformational interpretation of three-bond 1H-1H, 13C-1H and 13C-13C coupling constants and spin-lattice (T1) relaxation times (13C, 1H) in furanosyl rings. Relaxation studies will involve the use of DESERT and dynamic NOE NMR methods to obtain absolute 1H-1H internuclear distances, from which conformation will be assessed. Preferred ring conformations deduced by NMR will be compared to those predicted by MO calculations. D. Measurement and interpretation of unidirectional rate constants of furanose tautomerization by NMR. Activation parameters will be measured for each component reaction. Solution studies of simple furanoses will be extended to the ribonucleosides and oligoribonucleotides. Several GC-rich oligoribonucleotides, having base sequences identical to those found in the stems of E. coli tRNAglu, will be prepared containing perdeutero-ribofuranosyl residues to facilitate NMR studies of their solution structures. The proposed studies are a prerequisite to the pursuit of the longer-term objective of determining the molecular basis for the binding specificity between nucleic acids and proteins, and on elucidating the effect of sugar tautomerization on metabolic regulation.