Topological properties of the peptide bond in glycyl-L-threonine dihydrate based on a fast synchrotron/CCD-diffraction experiment at 100 K.
Topological properties of the peptide bond in glycyl-L-threonine dihydrate based on a fast synchrotron/CCD-diffraction experiment at 100 K.
复制标题
基于 100 K 快速同步加速器/CCD 衍射实验的甘氨酰-L-苏氨酸二水合物中肽键的拓扑特性。
作者：
B. Dittrich;R. Flaig;T. Koritsanszky;H. Krane;W. Morgenroth;P. Luger
甘氨酰-L-苏氨酸二水合物的电荷密度是从用Bruker CCD面检测器在100 K下收集的98405次反射的同步加速器数据集中提取的，分辨率高达d=0.38 A（sintheta/lambda = 1.32 A-1）。数据解释的“刚性伪原子”模型。的拓扑结构的实验密度进行了分析和比较与实验获得的拓扑结构的构成氨基酸和来自Hartree-Fock计算的孤立分子。位于共价键和氢键的电子密度的所有临界点，以及拉普拉斯算子，从而推导出肽和侧链键的定量拓扑数据。键拓扑指数的二肽比较以及与相应的债券在建设氨基酸，从而表明转移的原子和官能团的电子性质时，这些都是由巴德的分区。理论和实验结果之间的差异可以归因于晶体场效应。
The charge density of glycyl-L-threonine dihydrate is extracted from a synchrotron data set of 98405 reflections collected at 100 K with a Bruker CCD area detector up to a resolution of d=0.38 A (sintheta/lambda = 1.32 A 1). The data are interpreted in terms of the "rigid pseudoatom" model. The topology of the experimental density is analyzed and compared with the topology obtained experimentally for the constituting amino acids and to that derived from Hartree-Fock calculations for the isolated molecule. All critical points of the electron density at the covalent and hydrogen bonds, as well as those of the Laplacian, were located, thereby deriving quantitative topological data for the peptide and side chain bonds. Bond topological indices in the dipeptide compare well with those of the corresponding bonds in the building amino acids, thus suggesting transferability of electronic properties of atoms and functional groups when these are derived by Bader's partitioning. Discrepancies between theoretical and experimental results could be attributed to crystal field effects.