Chemogenomic strategies to expand the bioactive chemical space

Chemogenomics aims towards the systematic identification of small molecules that interact with the products of the genome and modulate their biological function. The establishment and expansion of a comprehensive ligand-target Structure-Activity Relationship matrix is following the elucidation of the human genome a key scientific challenge for the 21(st) century. Small chemical compounds are the first dimension of the ligand-target SAR matrix. Accordingly, the systematic expansion of the physically available and bioactive chemical space is a key objective of chemogenomics. The vital question is, how to enlarge the physically existing chemical space into the bioactive and drug-like spaces? Effective systematic expansion of the chemical space to reach a maximum of biological binding sites appears possible when conserved molecular recognition principles are the founding hypothesis for the design of the compounds. Such principles, including approaches focusing on target families, privileged scaffolds, protein secondary structure mimetics, co-factor mimetics, and DOS and BIOS libraries are summarized in this mini-review article.