有部分峰重叠时NOESY谱的全弛豫矩阵分析

采取用理论计算的NOESY峰强度代替NOESY谱中重叠的对角峰或交叉峰强度,用理论计算值和实验数据相结合的方法解决峰强度矩阵的完整化问题,用全弛豫矩阵分析法定量分析了谱中有部分峰重叠的天然有机化合物冬凌草乙素的相敏NOESY谱,计算出冬凌草乙素分子中各质子间的交叉弛豫速率,根据1/r_ij⁶∝σ_ij计算出相应的质子间距离,结果表明:用全弛豫矩阵分析法计算出的质子间距与分子力学计算得到的质子间距离完全一致。该方法能够用于谱中有部分峰重叠的天然有机化合物的NOESY谱的定量处理,可以为核磁共振方法确定分子在溶液中的三维空间结构提供可靠的结构参数

COMPLETE RELAXATION MATRIX ANALYSIS OF NOESY SPECTRUM IN WHICH A FEW PEAKS ARE OVERLAPPED

A complete relaxation matrix analysis method is used for processing the peak intensity matrix of phase sensitive NOESY spectrum of ponicidin in which a few cross peaks and diagonal peaks are overlapped. The initial structural model of ponicidin is established by using a series of structure calculation program such as WUPH and MM2. The theoretical peak intensity matrix of NOESY spectrum is calculated based on the molecular model of ponicidin. The mixing peak intensity matrix is consistant with experimental peak intensity matrix in which the intensities of overlapped peaks are replaced by theoretical peaks intensities. Then, the cross relaxation rates between protons are obtained by diagonalizing the mixing peak intensity matrix, and the inter-proton distances are calculated according to l/r_ij⁶∝σ_ij. The calculated results of complete relaxation matrix analysis method are in agreement with the inter-proton distances calculated by molecular mechanics.