Molecule Representation of Structures Based on Electron Diffraction

D Molecule Representation of Structures Based on Electron Diffraction Code (3D MoRSE Code)... 

D-molecule representation of structures based on electron diffraction 3D-MoRSE descriptors... 

D-MoRSE 3D-Molecule Representation of Structures based on Electron diffraction descriptors... 

Many years later, it was found that this characteristic of the descriptor could be used for the correlation of biological activity and three-dimensional structure of molecules. The activity of a compound also depends on the distances between atoms (such as H-bond donors or acceptors) in the molecular structure [91]. Adaptation of the RBF function to biological activity led to the so-called 3D-MoRSE code (3D-Molecule Representation of Structures based on Electron diffraction) [92]. The method of RBF calculation can be simplified in order to derive a descriptor that includes significant information and that can be calculated rapidly ... 

To calculate 3D-MoRSE descriptors (3D-MOlecule Representation of Structures based on Electron diffraction, or simply MoRSE descriptors), Gasteiger et al. ]Schuur and Gasteiger, 1996,1997] returned to the initial I(s) curve and maintained the explicit form of the curve. As the atomic weighting scheme w, various physico-chemical properties such as atomic mass, partial atomic charges, and atomic polarizability were considered. To obtain uniform-length descriptors, the intensity distribution I(s) was made discrete, calculating its value at a sequence of evenly distributed values of, for example, 32 or 64 in the range of 1-31 A . Clearly, the more the values are chosen, the finer the resolution in the representation of the molecule. 

In the three-dimensional (3D) approach the 3D structure (see Structure Generators) of a molecule is transformed into a structure code. This is performed by regarding every atom pair in the molecule as a point scatterer and calculating the center symmetric diffraction pattern of the molecule as it would be obtained from an electron diffraction experiment. Based on these equations the 3D molecular representation of structures based on electron diffraction (3D-MoRSE) code has been developed. The 3D-MoRSE code is calculated using the equation... 

Another code for representation of the 3D structure of a molecule with a fixed number of variables irrespective of the number of atoms in the molecule (3D MoRSE code) has been proposed by Soltzberg and Wilkins. This molecular description is based on methods used in the interpretation of electron diffraction data. The approach has been used successfully for both the simulation of infrared spectra... 

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