GRID probe-molecule interaction potential

Moreover, -> molecular interaction fields are calculated for each molecule in terms of similarity indices instead of the usual interaction potential functions, such as Len-nard-Jones and Coulomb potential functions. Similarity fields are calculated representing the similarity between molecules and different probe atoms. In particular, the similarity values at the intersections of the regularly spaced grid (1.1 and 2.0 A) relative to the yth physico-chemical property between the ith compound and a probe atom is calculated as ... 

The GRID method, like 3D-QSAR, uses a grid of points at which probe molecules are placed. In this case, however, it is the interaction with the active site of the enzyme rather than with potential drug molecules that is calculated. The most spectacular use of the GRID method was in the discovery of the anti-influenza drug Relenza . 

In fact, if a molecule is placed in an infinite, isotropic and even, very dense grid, the scalar field f calculated at the grid points must contain the same information, independent of the molecule s orientation and depending only on the potential energy of the selected probe and the mathematical functions representing the interaction. Thus f contains the whole information about the interaction properties of the molecule. 

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