Distance geometry analysis of the N.M.R. evidence on the solution conformation of bleomycin.
Distance geometry analysis of the N.M.R. evidence on the solution conformation of bleomycin.
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核磁共振的距离几何分析
DOI：
10.1111/j.1399-3011.1981.tb01978.x
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
Connolly,ML
中科院分区：
文献类型：
--
作者：
Crippen,GM;Oppenheimer,NJ;Connolly,ML
由n.m.r.导出的构象约束。通过距离几何方法，X射线数据和已知的立体化学已经用于研究Cu（II）：P-3A（博来霉素的生物合成前体）、Fe（II）：博来霉素：一氧化碳和Zn（II）：博来霉素的允许溶液构象的范围。实验数据被发现是自洽的，并导致以下观察结果。1)配位体的名称和二面角可从邻位耦合常数是不够的，以确定唯一的几何形状周围的金属。2)当仅调用五个博来霉素配体时（例如Cu（II）：P-3A或Fe（II）：博来霉素：一氧化碳），在金属周围的允许配位方案中存在相当大的自由度，但分子的一些区域具有良好确定的构象。3)引入第六博来霉素配体，如在Zn（II）：博来霉素中，大大限制了与锌配位的基团的构象自由度。距离几何方法的数据分析和实验设计的效用进行了讨论。
Conformational constraints derived from n.m.r. experiments, X‐ray data and the known stereochemistry have been used to investigate by the distance geometry method the range of allowed solution conformations for Cu(II): P‐3A (a biosynthetic precursor of bleomycin), Fe(II):bleomycin:carbon monoxide, and Zn(II): bleomycin. The experimental data have been found to be self‐consistent and lead to the following observations. 1) Designation of the ligands and the dihedral angles available from vicinal coupling constants are not sufficient to define uniquely the geometry around the metal. 2) When only five bleomycin ligands are invoked (e.g. Cu(II):P‐3A or Fe(II):bleomycin:carbon monoxide) there is considerable freedom in the allowed coordination scheme around the metal, but some regions of the molecule have well determined conformation. 3) Introduction of a sixth bleomycin ligand, as in Zn(II): bleomycin, considerably constrains the conformational freedom of the groups coordinated to the zinc. The utility of the distance geometry approach for analysis of data and design of experiments is discussed.