GRID crystal structure

Gitter, n. grating (as in Cryst.) lattice (latticed) screen grid, -ableitung,/. grid leak, -anordnung, /. (Cryst.) lattice structure, crystal structure. 

In a crystal atoms are joined to form a larger network with a periodical order in three dimensions. The spatial order of the atoms is called the crystal structure. When we connect the periodically repeated atoms of one kind in three space directions to a three-dimensional grid, we obtain the crystal lattice. The crystal lattice represents a three-dimensional order of points all points of the lattice are completely equivalent and have the same surroundings. We can think of the crystal lattice as generated by periodically repeating a small parallelepiped in three dimensions without gaps (Fig. 2.4 parallelepiped = body limited by six faces that are parallel in pairs). The parallelepiped is called the unit cell. 

Cruciani et al. [92] have developed the program Metasite for the prediction of the site of oxidative metabolism by CYP450 enzymes. Metasite uses GRID molecular interaction fields to fingerprint both structures of CYP450s (from homology models or crystal structures) and test substrates and then matches the fields. Zhou et al. [93] showed that Metasite was able to correctly predict the site(s) of metabolism 78% of the time for 227 CYP3A4 substrates. Caron et al. [94] used Metasite to predict the oxidative metabolism of seven statins. 

Figure 1.4 Orthogonal views of the crystal structure of the tetracationic grid 7 (the —CONHCH2CH2OH groups of the ligands are replaced by purple spheres at left).

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