title: The signature molecular descriptor. 1. Using extended valence sequences in QSAR and QSPR studies.
abstract: We present a new descriptor named signature based on extended valence sequence. The signature of an atom is a canonical representation of the atom's environment up to a predefined height h. The signature of a molecule is a vector of occurrence numbers of atomic signatures. Two QSAR and QSPR models based on signature are compared with models obtained using popular molecular 2D descriptors taken from a commercially available software (Molconn-Z). One set contains the inhibition concentration at 50% for 121 HIV-1 protease inhibitors, while the second set contains 12865 octanol/water partitioning coefficients (Log P). For both data sets, the models created by signature performed comparable to those from the commercially available descriptors in both correlating the data and in predicting test set values not used in the parametrization. While probing signature's QSAR and QSPR performances, we demonstrates that for any given molecule of diameter D, there is a molecular signature of height h </= D+1, from which any 2D descriptor can be computed. As a consequence of this finding any QSAR or QSPR involving 2D descriptors can be replaced with a relationship involving occurrence number of atomic signatures.
authors.affiliation: Sandia National Laboratories, P.O. Box 969, MS 9951, Livermore, California 94551, USA. jfaulon@sandia.gov
authors.forename: Jean-Loup
authors.initials: JL
authors.lastname: Faulon
authors.forename: Donald P
authors.initials: DP
authors.lastname: Visco
authors.forename: Ramdas S
authors.initials: RS
authors.lastname: Pophale
mesh_terms: D000465:Algorithms; D017320:HIV Protease Inhibitors / Q000737:chemistry / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D008956:Models, Chemical; D015394:Molecular Structure; D000442:Octanols / Q000737:chemistry; D021281:Quantitative Structure-Activity Relationship; D012984:Software; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D017320:HIV Protease Inhibitors; D000442:Octanols; D014867:Water