Descriptor autocorrelation

Broto, P., Moreau, G., Vandycke, C. Molecular strucmres, perception, autocorrelation descriptor and SAR smdies system of atomic contributions for the calculation of the octanol-water partition coeffident. Eur. J. Med. Chem. 1984, 79, 71-78. 

Broto, P., G. Moreau, and C. Vandycke, Molecular Structure Perception, Autocorrelation Descriptor and SAR Studies. System of Atomic Contributions for the Calculation of the n-Octanol/Water Partition Coefficients. Eur. J. Med. Chertu-Chim. Then, 1984 19,71-78. 

The work of Schneider et al. [6] first focused on the scaffold-hopping ability of autocorrelation descriptors, in this case topological pharmacophores. The general description of the atoms with pharmacophore atom types in combination with the decomposition of molecules into atom pairs was shown to be especially successful in finding new molecules with significant different molecular scaffolds, maintaining the desired biological effect. 

ATS descriptor -> autocorrelation descriptors (O Moreau-Broto autocorrelation)... 

Autocorrelation descriptors can also be calculated for 3D-spatial molecular geometry. In this case, the distribution of a molecular property can be a mathematical function /(x, y, z), x, y, and z being the spatial coordinates, defined either for each point of molecular space (i.e. a continuous property such as electronic density or molecular interaction energy) or only for points occupied by atoms (i.e. atomic properties). An example of 3D autocorrelation descriptors are the - spectral weighted invariant molecular descriptors defined by - SWM signals. 

The plot of ordered sequence of autocorrelation descriptors from lag zero to lag L is called the autocorrelogram, usually used in similarity analysis. 

The most well-known autocorrelation descriptors are listed below. 

Average spatial autocorrelation descriptors are obtained by dividing each term by the corresponding number of contributions, thus excluding any dependence on molecular size ... 

Autocorrelation descriptors calculated for 3D-spatial molecular geometry are based on interatomic distances collected in the -> geometry matrix and the property function is defined by the set of atomic properties. 

GAP HOMO-LUMO energy gap -> quantum-chemical descriptors Geary coefficient -> autocorrelation descriptors general aN-index -> determinant-based descriptors... 

Kier alpha-modified shape descriptors autocorrelation descriptors... 

Molecular descriptors are usually classified into several classes by a mixed taxonomy based on different points of view. For example, descriptors are often distinguished by their physico-chemical meaning such as - electronic descriptors, - steric descriptors, lipophilicity descriptors, -> hydrogen-bonding descriptors, - shape descriptors, charge descriptors, - electric polarization descriptors, - reactivity descriptors, moreover, on the basis of the specific mathematical tool used for the calculation of the molecular descriptors, - autocorrelation descriptors, -> eigenvalue-based descriptors, -> determinant-based descriptors, - Wiener-type indices, - Schultz-type indices can be distinguished. 

Procedure b) was adopted to obtain a set of molecular - autocorrelation descriptors calculated separately from each axial spectral representation. These descriptors were called Spectral Weighted Invariant Molecular descriptors (or SWIM descriptors). 

For each considered weight, a molecule is represented by a vector of autocorrelation descriptors ... 

Examples of applications of the rules to obtain uniform length descriptors are - EVA descriptors, - topological charge indices, atomic walk count sequence, -+ SE-vectors, - molecular profiles, -> 3D-MoRSE descriptors, - autocorrelation descriptors. 

Broto, P., Moreau, G. and Vandycke, C. (1984a). Molecular Structures Perception, Autocorrelation Descriptor and SAR Stuffies. Autocorrelation Descriptor. EurJMed.Chem., 19,66-70. 

Devillers, J. (2000). Autocorrelation Descriptors for Modeling (Eco)Toxicological Endpoints. In Topological Indices and Related Descriptors in QSAR and QSPR (Devillers, J. and Balaban, A.T., eds.), Gordon Breach, Amsterdam (The Netherlands), pp. 595-612. 

P. Broto, G. Moreau and C. Vandycke. Molecular stmetures perception, autocorrelation descriptor and SAR studies. Perception of molecules topological stmeture and 3-dimensional stmeture. Eur. J. Med. Chem., 19, 61-5 (1984)... 

Devillers J, Domine D, Guillon C, Bintein S, Karcher W. Prediction of Partition coefficient (logPoct) using autocorrelation descriptors. SAR QSAR Environ Res 1997 7 151-72. 

We have used transferable atom equivalent (TAE) descriptors [116,117] that encode the distributions of electron density based molecular properties, such as kinetic energy densities, local average ionization potentials, Fukui functions, electron density gradients, and second derivatives as well as the density itself. In addition autocorrelation descriptors (RAD) were used and represent the molecular geometry characteristics of the molecules, while they are also canonical and independent of 3D coordinates. The 2D descriptors alone or in combination with the latter 3D descriptors were calculated for 26 data sets collated by us from numerous publications. These data sets encompass various ADME/TOX-related enzymes, transporters, and ion channels as... 

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