Transformation of Peptides into Non-Peptides. Synthesis of Computer-Generated Enzyme Inhibitors: Computer-Assisted Drug Design

With the intent of discovering novel molecular scaffolds for designing protease inhibitors, the computer program GrowMol was used to generate peptidemimetic inhibitors of aspartic proteases. Beginning with the X-ray crystal structure of A66702 complexed to pepsin, GrowMol successfully generated a series of known cyclic inhibitors of pepsin in which the cysteine side chains in the P1 and P3 inhibitor subsites are connected. GrowMol also created a series of novel urea-derived inhibitors of pepsin, a series of α,α-disubstituted amino-alcohol-derived structures, and a series of cyclohexanol-derived inhibitors in which the core portion of the inhibitor lacks nitrogen. The paper describes the iterative process of selection and synthesis of computer-generated structure, determination of activity, and reassessment of potency with respect to the beginning crystal structure. These efforts led to the synthesis of analogs 9–12 which are novel pepsin inhibitors with moderate inhibitory activity. Attempts to crystallize these inhibitors in the active site of pepsin to determine if compounds 9–12 bind as predicted by GrowMol are in progress

A Src SH2 selective binding compound inhibits osteoclast-mediated resorption

AbstractBackground: The observations that Src−/− mice develop osteopetrosis and Src family tyrosine kinase inhibitors decrease osteoclast-mediated resorption of bone have implicated Src in the regulation of osteoclast-resorptive activity. We have designed and synthesized a compound, AP22161, that binds selectively to the Src SH2 domain and demonstrated that it inhibits Src-dependent cellular activity and inhibits osteoclast-mediated resorption.Results: AP22161 was designed to bind selectively to the Src SH2 domain by targeting a cysteine residue within the highly conserved phosphotyrosine-binding pocket. AP22161 was tested in vitro for binding to SH2 domains and was found to bind selectively and with high affinity to the Src SH2 domain. AP22161 was further tested in mechanism-based cellular assays and found to block Src SH2 binding to peptide ligands, inhibit Src-dependent cellular activity and diminish osteoclast resorptive activity.Conclusions: These results indicate that a compound that selectively inhibits Src SH2 binding can be used to inhibit osteoclast resorption. Furthermore, AP22161 has the potential to be further developed for treating osteoporosis